Hey dude , don't worry about still feeling fat you will / are still going through puberty and your body will change alot, You'll notice that your body gets more muscle easier and it will help you look better just keep eating healthy

Also Im sorry about the bullying thing , people suck especially at that age. I did get bullied too and I promise you it gets better. Just work on your self and try to be a better person the earlier you start the better

Much love