Okay so on a daily basis i'm eating less than the recommended 2000 calories a day, but i don't think i'm losing any significant amount of weight, why is this?
It various from day to day but usually i can eat anything between 600-1500 calories a day, if i eat fewer calores, like about 600-1000 then i will feel good and better the day after, but if i eat a lot more, like around 1500 i feel terrible, and the next day i feel so bloated and like i have put on weight, but i'm still eating less than 2000!
What am I doing wrong?

A few questions ; what is your gender, how old are you, how tall are you and what do you weigh now? You speak of the "recommended" 2000 calories a day. 2000 calories a day is the recommendation for an average adult male. But, depending on the factors I've questioned above, your recommended intake may be substantially higher or lower than that. For starters, I'd say stick to a consumption level that makes you comfortable. If that happens to be 600-1000 calories, then stay with that. Also, keep in mind that it's not just about diet but exercising as well. Exercising will help you burn fat and increase your metabolism so that your body makes more efficient use of the calories you consume.

are you exercising? you have to exercise to help burn calories. eating less calories is not the only thing that makes you lose weight. you have to increase your metabolism in order to lose weight

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This girl has issues with her weight, she's underweight already but still wants to lose more.

Check out the above link.