Advice on how I am feeling

Hello,

Lately, I have been feeling depressed and down with my moods, but this has increased after I had a falling out with a friend who genuinely insulted me after knowing each other for nearly 5 years. I have cut this person out of my life, but I can't get the insults or what he said to me in his messages. 

He insulted my Intelligence, which is hurtful sadly I have had people say this to me all my life for whatever reason, I am not low functioning, I have high functioning but I am not that upset about that insult In particular.

I am more hurt about what he thought, calling me a waste of space, a wasteful friend and a distraction, he also said I cannot commit to anything, and he turned into a massive pri*K after he joined the German Police. I have talked countless times to him about what I wanted to do, which has always been to join the UK Police. Well yes, I was annoyed that people can easily join a job and get accepted without even thinking about it. But I was happy he joined, but then he knew I felt down about it but I never expressed it to him. But he used to come home and gloat about his new job blah blah and How I would never get in the Police here. 

But sometimes I sit and just think maybe he was right, perhaps I am a waste of space and stuff, and it annoys me that he had no sympathy for what he was doing. I just feel I am digging myself a deeper hole and I can't not get out of it. I have started to get a really bad migraine again because I am constantly stimming and overthinking about everything. 

If you have any advice for what I can do to cheer my moods up or help me stop overthinking or stimming, I would greatly appreciate it.