Yes I'm currently going through that right now and it's hell. It's all my fault. I'm so sorry you're feeling this too. I suggest you let yourself feel the extreme pain and let it all out, whether that be crying or screaming or writing down your feelings just for yourself. Then after you get it all out, you can hopefully find something to comfort you like music or something to watch/read. It will help distract you and bring you back to thinking about yourself and your own interests instead of this person. But I know this will only make things slightly tolerable. I really hope you can find enough comfort to rest, and please be easy on yourself while going through this.