I'm sorry you're going through this. I'm 15 as well and have paranoid symptoms, but stemming from my PTSD.

I think the only real way to find out is to go through with seeing a psychologist. I'm in therapy and am on medication and it's really helped me so far. It could be a number of different things, so that's the best option. I wish you luck on your journey, and I hope things definitely clear up for you.