Getting over him.
hey. I'm currently struggling to get over my ex. He used to bring me down and blame all his problems on me (he has depression) and it made me really anxious. But he's my best friend and I miss him a lot. It makes me upset. I don't know I'm so lonely and I feel like I have no one to talk to. Feeling so alone.
this kind of relationsship is toxic and you know that. unfortunately, sometimes the people we like aren't all that good for us. in your case its directly bad since he blames you (his depression is a factor but he shouldnt take it out on you and you shouldnt take it either)
yuo can listen but dont be a dumping ground.
dont cut him out of your life completely since you do care for him but demote him to a person whose opinions no longer shape your own being.
you should also try to find new friends who make you feel appreciated as yuorself. i know this is all easier said than done... but we cant change without steppin out of the comfort zone.
Hmmm, he is your best friend? Maybe you nee to reconsider that if he makes you feel so bad. Best friens are supposed to support you, and make you feel good.
Sometimes the toxic relationships we have are the hardest to get away from. You should not bring yourself down because of those around you doing it. It could be best to give each other some time and then talk about things that you are both concerned about in the relationship. I agree that we should have friends that love and support us as who we are not negative. We all deserve positive reactions and people in life.
So sorry to hear that you are going through such a difficult time. It's so easy to feel the pain of that kind of behavior but forgive it, over, and, over, and, over again. In my experience, one of two things happen. You either internalize it and accept it to be true, or, walk away from it.
You made the healthy, really difficult choice. You should be so proud of yourself. If you can do this, well, (feel free to replace the "w" with an "h"), you can do just about anything. After you heal, consider the possibilities. Maybe a little space while you go through the healing? It's like giving up an addiction, and, it's so easy to fall back. I know. I had a relationship just like that, and, it lasted for almost twenty years. Please reach out if you ever want to talk! Again, be proud!
I'm going through something similar.. you get sad and then you get angry. Moving on and meeting people who are nicer to you and better for you shows that you're better off without him. 
There are a lot of people in this world and if you learn to take care of yourself the best you can, it will raise your chances of finding someone much better for you.