I also lived with someone addicted to meth and it was definitely insanity. The addict becomes so sick that by extension, those that live with them become sick too. I finally had to separate from this person and go no contact with him. The distance from him and the situation made me realize how bad things were and how toxic the situation was.
I remember being so ANGRY at the destruction meth had brought into my life. I was angry, depressed, anxious, sad etc. Meth had taken a wonderful, compassionate person and replaced him with someone who only cared about getting high on meth. If I hadn't seen with my own eyes how dramatic the change was with this person, I wouldn't have believed it.
I had so many good things going on in my life (health, good job, home, supportive family and friends, etc) but I wasn't enjoying any of it. I got to the point where I was so angry at all the damage that was caused by meth that I decided I was not going to let meth take anything else from me. In fact, I was going to be damned if I let it rob me of another moment of peace or happiness.
I had to make a conscious effort to truly LIVE again, not just survive (which is what I had been doing before).
As tempting as it is to isolate yourself during this time, don't do it. It's ok to have some time on your own, to process things and move forward, but don't allow the sadness and grief to consume your life. Go out for a walk, have lunch with friends, do something positive for YOU. It's going to take some effort, but I think you'll feel better afterwards, you'll start to feel human again. Lean on your friends and family for support and keep posting here on SR. Believe me, you WILL get through this. One step at a time, but you will get through this