So I've just been told I'm eating too much..

NO! You're on the right track!

Whoever told you that is a total idiot.
No, you should not only eat what you burn, if you mean burn in exercise.
You should eat at least your bmr, which is what you burn just by being totally sedentary/in a coma, preferably more.
You should try not to eat below 1200 a day, and eat back calories you burn off through exercise, or at least some of them, as your body cannot run very efficiently on really low amounts unless you are extremely overweight to begin with, which you are not.

Also if you are eating 1800-2000 and burning 1300 in exercise, you are only netting 500-700 ?

Calculate your Total Daily Energy Expenditure here: http://www.health-calc.com/diet/energy-expenditure-advanced?tmpl=component&print=1&page=

This will tell you how many calories you should be eating to maintain.

Soooooo not true! If anything,you're still not eating ENOUGH with those crazy burns you have!!! Check out the Eat more to weigh less group here on MFP...you should at least be netting your BMR, which is basically the minimum your body needs to function organs, etc...

I'm 5'1" 122-123 lbs. I eat around 1800-2000 cals a day and burn around 1300 and sometimes more..
I've been told I should only eat as much as I burn, so If I burn 1300 I should only eat 1300 total..is this true?
Because now I just feel horrible and feel all the work I've been putting in is garbage...

Who told you that?

If it's some random person, screw them. It's horrible advice. Your body will start burning both fat and muscle to feed itself, and you'll get in trouble right quick. That's like anorexia on steroids. It's basically the equivalent of fasting if you weren't exercising, and you can't keep it up for long.

If it's your doctor, get a second opinion or ask them seriously about it.

Do you have some specific medical condition (other than being overweight) that your doctor is concerned about, a concern that would outweigh the damage you are about to do to your body and in particular your lean muscle mass?

Are you VERY overweight and need to lose weight fast to support a surgery or other procedure that will correct something severe?

And if either of the above is true, has your doctor given you a specific diet plan to follow or told you to focus on specific mactonutrients such as protein or complex carbohydrates, or has he/she just said (in effect) "eat nothing".

It says my Total Energy Expenditure is 2,628..what does this mean?

That means that given your stats and activity level, that's how many calories it takes for you to maintain your current weight.

I would say the amount of exercise you are doing sounds all consuming and excessive.
I cannot imagine anyone sustaining that amount of exercise for life, and in the end that will only lead to issues with keeping weight off.
It is much healthier to stick to around an hour of cardio per day, and to do the rest through eating a healthy diet.
You will totally exhaust yourself doing that much.

& I take a brisk walk for at least 3 hours a day, then run/jog on the treadmill for at least 2 hours....and sometimes ride my bike.

I just looked at your profile - you are trying to lose 11 pounds. This ain't the way to do it.

Do yourself a big favor (as my previous post stated, unless you are doing this on the advice of a doctor, and if you are I'd have a long talk with Doc about it and why they want you to do this to yourself with 11 pounds to lose!)...

Go back through the setup process, and choose your honest lifestyle not including exercise. Select "1/2 pound a week" or if you're in a huge hurry "1 pound a week" (but 1 lb/wk is going to be hard to sustain with 11 to go, trust me). Log all your exercise and eat at least most of those calories back.

Eating "net zero" calories (burning every calorie you eat in exercise each day) is WEAPONS-GRADE FOOLISH (in the absence of a specific medical condition or some other issue that a trained and competent medical professional is coaching you through).

Whoever told you that is a total idiot.
No, you should not only eat what you burn, if you mean burn in exercise.
You should eat at least your bmr, which is what you burn just by being totally sedentary/in a coma, preferably more.
You should try not to eat below 1200 a day, and eat back calories you burn off through exercise, or at least some of them, as your body cannot run very efficiently on really low amounts unless you are extremely overweight to begin with, which you are not.

Also if you are eating 1800-2000 and burning 1300 in exercise, you are only netting 500-700 ?

^^ What she said!!

& I take a brisk walk for at least 3 hours a day, then run/jog on the treadmill for at least 2 hours....and sometimes ride my bike.

Be careful you are not becoming exercise-obsessed. Over doing it working out is just as unhealthy for your body as over eating. 5+ hrs per day of working out when you're not a professional athlete can be very damaging to your body.

It's totally possible to burn 1300... I just burned 1500 on Monday running for 2 hours and 15 minutes. I eat all my exercise calories and lose.

Sounds right to me. I am 5' and eat the same as you, close in weight too.

I'm 5'1" 122-123 lbs. I eat around 1800-2000 cals a day and burn around 1300 and sometimes more..
I've been told I should only eat as much as I burn, so If I burn 1300 I should only eat 1300 total..is this true?
Because now I just feel horrible and feel all the work I've been putting in is garbage...

First of all, NO. You are NOT eating too much. Today, I have eaten over 2000 calories and burned off only 760. I'm a little bigger than you...about an inch taller and 30 pounds more. :-/

You burn off more than just what you EXERCISE off! You are still on a big deficit!

Second, how are you burning that much as little as you are? O.o

Third, we're neighbors! I'm in Port Richey.

First things first - get rid of the amount of exercise you are doing!