I'd would think that this is just a faze that your going through. Perhaps you have not been doing as much physical activity of late and do not need the extra food? And, I think that the pills would not be affecting you because you said you took them a long time ago so they have probably run their course. But please, if you are losing a lot of weight please speak with a adult you fell comfortable with. :)
Hope this helps,
-Norden77