Too much excerise

Too much is when you can not recover. If you feel good then no prob, keep doing it. You can exercise even 10 times a day if your body can recover, whatever works for you. You need to learn your body and see if it is too much for you, if you have any signs of over-training. Cos too much is subjective and depends from person to person, from your fitness level, genetics, etc.

I used to do 10k runs every day and sometimes even twice a day. Plus strength training. Now I take one day a week off and don't strength train every day cos I'm on a different program. But I was fine. Professional athletes train up to 8 or 12 hours a day. So no there is no such thing as "too much", it depends.

Yes, there is definitely such a thing as overtraining. If you want to get stronger, improve distance, endurance, etc you absolutely have to incorporate rest days into your workout plan. Typical symptoms are fatigue, decreased immunity, insomnia, depression, inability to progress in training, etc. Pretty much everything that is the opposite of why most people train.

If you're just working out for the sake of burning calories, I would at least advise one total rest day and one active rest day where you do something much lower intensity than normal. Hard to give more specific examples without knowing what you do for activity but let's say you do a lot of running - go for a gentle walk or leisurely bike ride.

You didn't give much detail as to your workouts but for most, otherwise healthy people, an hour or so a day of activity is easily sustainable virtually indefinitely as long as you're mixing up intensity etc (ie not doing HIIT 7 days per week) - we evolved to do hard physical labour, that's why exercise is good for us; we're just doing what we evolved to do.

On the other hand, if you were training like an Olympic athlete yes, it's easy to overtrain

Muscle groups need a rest day from weightlifting, which tears muscle fibers. The rest day lets those fibers knit, which in turn strengthens the muscle.

See, for example:
http://www.muscleandfitness.com/workouts/workout-tips/rest-your-body-grow-your-muscles

Cardio is harder to gauge, so listen to your body. I have over-trained on cardio, which has resulted in colds and fatigue.

See, for example:
http://www.rice.edu/~jenky/sports/overtraining.html

The most common symptom is fatigue. This may limit workouts and may be present at rest. The athlete may also become moody, easily irritated, have altered sleep patterns, become depressed, or lose the competitive desire and enthusiasm for the sport. Some will report decreased appetite and weight loss. Physical symptoms include persistent muscular soreness, increased frequency of viral illnesses, and increased incidence of injuries.

The good news is that thinking one must exercise every day is not hard-wired; it's a habit of thinking that can be changed with practice. Maybe plan a calendar in advance with built-in rest days that give you "permission" to take the time off. Maybe record how you feel, physically and emotionally, after each workout for purposes of feedback. If rest days are hard to plan, maybe plan lighter workout days. Find the right tools for you that will help you find the balance you need.

I had the same issue, I had gotten into a routine and was afriad if I took a rest day, I'd lose my momentum, which is why I do yoga once a week. It allows me to slow down, not worry about my heart rate and it makes me feel relaxed and reinvigorated. Depending on the weather, I will take my dog for a walk, but its pretty casual. Sometimes a short walk around the neighborhood, sometimes I take her to the park and we'll walk for an hour, a slow leisurely walk.

yes...there is such a thing as too much exercise. really, you should have days of varying workout intensity with at least 1 rest day per week if you're pushing yourself pretty good. your fitness routine really should be deliberate and pretty well balanced for general fitness...i.e. 45-60 minutes of resistance training 3-4 days per week and 45 - 60 minutes of cardio 3-4 days per week...you will get the most bang for your buck keeping these activities on opposing days.

I'd also add that if you're training for something then train for that...don't train for that and some other thing and some other thing...don't be me. Last year I was all hot to trot as I had vastly improved my fitness level...I was training for a sprint triathlon which was a lot of volume in RE to swimming and running and biking and doing brick work, etc...on top of that I kept trying to lift as if I wasn't doing all of that other stuff...and then on top of that I decided I really wanted to do cyclocross so started training for cyclcross season as well.

End result of all of that was that I ended up with a partially torn posterior tibial tendon in my left foot and the one in my right foot was well strained. This meant that all of my tri training was down the drain because I could not participate in the event...I missed the entire cyclocross season and spent about 3 months rehabbing my feet which totally messed up my lifting routine and set me back a good long ways on my lower body work. Good times....

Now, I make sure I'm getting adequate rest and listening to my body. I make sure I get at least one rest day per week...which doesn't mean I sit on my *kitten*...it means I just don't go out and do any vigorous activity...I just take it easy. I also de-load my lifting and all other activity every 5th week....these rests and de-load weeks are a part of my routine...so I'm not breaking routine...so if I'm not breaking routine then I don't have to get back into routine...it's all a part of the plan.

For me, too much exercise is doing more than you know you'll be able to do long term, and exercising so much that you can't fuel your body properly for it.

Yep - this!^

Exercise is a lifestyle change to (for me anyway). Also strength training (for me, again) is to keep existing muscle mass....I need to eat just enough to make that happen.

as long as your body feels good you are fine. I take one day 'off' but on that day I usually take a 3-4 mile walk just to stretch my legs. As long as you enjoy what you are doing and your body is not fighting you - go for it. I love to work out and feel like if I don't work out each day something is missing. That is why I opted for the walk day. You are doing great ....keep it up