Why aren't I losing weight?!

Why aren't I losing weight?

I'm 16 years of age, 173cms, and I weigh 70kgs. I'm on Aripiprazole and Fluoxetine tablets. For two weeks, I have carefully watched my diet, exercised on my exercise bike - I burn anywhere between 200 and 400 calories a day - and I haven't lost a single pound. I recently discovered that the Amulsulpride I was on had a weight gain side effect, so I've stopped taking it. I also know that Aripiprazole has a very, very rare - less than 1 in 10'000 people have it - weight gain side effect. I weighed myself yesterday - eleven stone exactly. I just weighed myself now - 11 stone 5. What the hell is going on with my weight and how do I slim down to 64kgs?
Also, I am a severe haemophiliac and can't do most sports.

5 days ago
I don't have a man's intake of 2500 calories and I've just burned 255 calories just now. I burned 150 earlier and 200 in the morning. And that's all happened today. Good enough?

you are not losing wait because you are gaining muscles