Constant negativity. Not diagnosed!

It's more of a vibe than a feeling. It's usually that I am very happy but suddenly I am reminded of things and figures and people which suddenly seems to make me sad. I recently experienced a very bad low which made me cry when I shouldn't have. For starters, I have been feeling this way since 6th grade (that's when I remember it happening for the first time). I couldn't sleep in my own bedroom because of being scared (it was a new place but I had a habit of sleeping on my own). That's when I was terribly scared. I couldnt sleep at night, stopped going to school regularly and at all, was afraid of darkness and it would make me cry because I was so afraid. I used to use social media but ran away from every platform as it seemed scary as well. I am in 10th grade now. I do feel stronger but I have been closed off for almost two years now and I simply reciprocate whatever people want me to feel in order to avoid fighting for how I feel but I really want to get rid of myself. Not diagnosed