Most Helpful Guy
If you really are too "skinny", you should talk to your doctor about it. But going on with these difficulties with your boyfriend only hurts you. You probably should have broken up with him ages ago, not because he is wrong or that you are, just because your differences are causing you depression. Find someone you can be happy with.
Most Helpful Girl
If you feel like it can't get better then yes you should break up.
before taking such decision, you should try to understand where he came from. I really don't know how skinny you are. It's obvious a problem for you. Did he tell you this because he's concern about your health or was it just coming from the fact that he's more into curvy women. How did he react when you explained it to him.
The main thing here is for you to know if he was genuinely concerned and if you could both move past this.
Sometimes, you have to work on relationships and hold on. Depression can also affect your decision. Also, have you seen a doctor? it's not good to fight this alone