I Can't seem to Lose any more weight, Plz help

I have been having trouble lately losing any weight, I am 16 years old and I originally started off at 169lbs and I have successfully made my way down to 151 lbs, however, my goal is 135lbs and I just can't seem to get the scale to go down past 148lbs for more than 2 days. I know I still have weight to lose and I have just started little training sessions every day to burn extra calories. The main problem is that I can't eat more than 800 calories a day even after burning over 300 calories. I am choosing healthier foods and avoiding all fast foods, fatty foods, and high carb foods. I also usually feel hungry only 1 hour after eating. I would love some advice on what to do to lose the extra pounds!
Do you mean you are on only eating 800 cals a day? If so, that is a problem. Too little calories can cause certain organs to work harder, causing your metabolic system to slow down as a way to conserve your body's energy.