How many calories should you burn in a day?

I don't think there is an appropriate amount. Regardless, the healthy range to lose is between 1-2lbs a week and that depends on how much you have to lose. The closer you get the less you will lose every week.

Besides you can't out exercise a bad diet. Meaning that it all comes down to calories in vs calories out and doing so in a healthy sustainable way. You most likely didn't pack on 2-3 lbs a week to get to where you are now so don't expect the road to losing it will be any faster or easier. If you wanna reach your goal and keep it off you want to find something sustainable like enjoying the foods you like in moderation keeping at a deficit while exercising regularly and not like a maniac. The fact thy you are exhausted probably means you are working out too much, not eating and most likely both.

I highly suggest you use the search function for "sexypants" and read that thread and follow these advices

Edit: as for the cabbage/prune/laxative part, try fibers with a lot of water, reduce cheese and if it doesn't work go see a doctor.

A pound equates to 2200 calories. So to lose 2 pounds you would have to have a calorie deficit of 4400 calories for the desired period of time.
Of course, that is in a perfect world.
Still you could use it as a rule of thumb.

Also determine your BMR (basal metabolic rate) using any of numerous online calculators.
Then you can determine how much exercise-burnt calories you need to add to outstrip your calorie intake.

Again, all in a perfect world.

Re: your p.s.
Think about adding old-fashioned oatmeal (not the instant). Lots of fiber (and other benefits).

1000 is enough! more then enough, I burn only around 300-600 and that's heaps for me! I know because I'm small and don't weigh much but 1000 is still a great effort, and losing weight rapidly may not be the best idea as you may tire out your body and cause damage!

If you are finding it hard to lose weight whilst burning 1000 calories, maybe eat a bit less!

See a professional please.

You're young (probably not 19). You want fast weight loss. You take laxatives. your diary is frightening.

Talk to someone in your real daily life.

Gonna second other posters and say you need professional help. You are heading to, if not already, eating disorder and trust me that is the last thing you want.

See a professional please.

You're young (probably not 19). You want fast weight loss. You take laxatives. your diary is frightening.

Talk to someone in your real daily life.

^this.

My mom's fine with my eating.

I really doubt your mother is a professional or else she would not be fine with it. You are not eating enough and if you continue down that road you are going to damage your body and that can take a long time to recover from and will only bring bad to your life. I don't mean to frighten you hun, but I have been down that road and I promise this is not the way to go.

You probably can't 'go' often because theres nothing much in your stomach to push out. Your mom might be happy with your intake but if her relationship with food is similar to yours that might be why? I don't know you or your mom, but all i do know is that based on the information you have given us here you work out a lot and barely eat. THAT is why you're lacking in energy and why you're struggling to perform basic bodily functions.

Honey, you need to address this to be healthy.