I Need Professional Advice

Water retention from exercise.
Weight loss isn't linear.

Exercise causes muscle inflammation, which results in fluid retention. This is why your weight drops when you rest a day or so.

If you need professional advice, you need to go your doctor. We are not professionals, we are a bunch of internet strangers on a path similar to yours.

Be sure to talk to your parents about your weight loss questions too, as they might be able to help you.

If you want professional advice then you should talk to a doctor.

Bodies do weird things with weight because of water - sodium, hormones, exercise can all have an impact on how much water you retain and therefore how much you weigh. You're not going to see a loss every single day - weight loss isn't linear.

As a female you also have a ton of hormones to deal with around certain times of the month. If you can't handle seeing the weight for what it is everyday, then I suggest picking a day in your cycle and weighing on that day every single month instead.

try changing your cardio/ weight training routine. Just like with weight a plateau, your body can get used to the same old exercise routine. also vary your calories...eating anything less than 1200 is too low for a good amount of people. As a general rule if you are adding calories to your diary based on what a treadmill or other machine tells you be wary...they can often add 20-30 percent to your actual calories burned. Your body adapts to your activity, strength training, calorie intake etc. Mix it up...if you lose weight at,say for example 1700 calories, try eating 1300 one day and 1900 the next....dont go too high or low though. Vary your workouts, type of workouts, time of workouts, or try doing an early morning and evening workout....The point is: shock your body until it responds. Once it does try for some consistency, but there is NO magic formula...NO one diet, NO one workout that is the best or universal. Experiment until you find what works. Have fun with it. If all else fails...see a nutritionist, a personal trainer, or even your doctor. Best of luck

I don't know why you're only seeing weight loss when you don't exercise. Notice, I said "seeing weight loss", not "losing weight". Just because you're not seeing it on the scale doesn't mean you're not losing (at least on a short term like 1 day or 1 week). It could be that exercising causes you to retain water and you lose that water when you take a day off.

Or it could be a matter of how you eat your calories back (as in, what kind of food). I'm on a low-carb diet, so I'm very aware of how carbs effect your body's ability to burn fat. I also remember that my post-workout food was always carb-heavy because that's what I was craving.

But 1-2 lbs of loss in one week is very good, especially if it's mostly consistent week-to-week. I've never heard of a healthy weight loss plan that does better than that. Low-carb diets lose more to begin with, but that's mostly water weight.

I seriously think you're doing everything right. And I don't think you're going to get a better answer than this, because if there was a healthy way to lose more than 2 lbs/week everybody would be doing it.

Maybe you should experiment with taking 2 rest days a week: one in the middle of the week and one on the weekend. See if that changes anything.

On another note: you titled this "I Need Professional Advice", but MFP is not a place to find Professional Advice. Everybody here is an amateur, and most of know very little beyond our own experience and our own research (which is biased towards our own experience). If you want professional advice, you're going to have to hire a professional.