help?

Hello, my name is Martijn. I’m a 15 year old boy. I’ve had a depression before when I was about 12. It lasted about a year. Ive been in therapy and been taking medication since then. The following 3 years of my life have been great. But half a year ago, I started fealing anxious again.  strange, violent toughts towards me and the people around me popped op in my head. I often felt empty, as in a dream but i couldn’t ‘wake up’. It felt like I didn’t use my medication anymore, wich I have to control my anxiety. Since then, I started feeling worse. I talked about it with a psychologist and it appears to be a normal to feel side effects, as, I’m in puberty and growing a lot lately.  My medication has been changed from 20 mg to 30 mg. After 3 weeks, this didn’t appear to be the solution. It got worse and worse. I’m back on 20 mg since then. But that didn’t clear anything. the anxious feeling of hurting myself or someone near my got stronger. I did’t dare to go to school anymore, because I might get the urge to jump in front of a train or something like that. I didn’t dare to be in a high building because i might jump out of the window. This thoughts made me so depressed and upset that I wouldn’t even care anymore if I jumped out of a window or something like that. I’m trapped in my thoughts. Still I have no idea why I would ever do something like that. I have it all, a loving family, a nice girlfriend and great friends. all the things to have a happy life. But I do not. I have no Idea how it will get better, and if I ever feel happy again. At the moment, I can’t even wait for a train because i can’t stop thinking about jumping in front. I really want to get happy again. I really try to see the beautiful things in life but on moments like these,  I just can’t see them. I hope somebody can help me. (I’m sorry for my bad English,  I’m dutch)