Why does my mother treat me like this?

I'm sorry your mom is this way. Some people just don't know what to do about things they don't understand. Sounds like she is lashing out at you in frustration, maybe thinking you seeing her upset will make you 'snap out of it'. Remember, suicide is PERMANENT. You never get a 2nd chance. Problems are oh so temporary. Please talk to someone you can trust or seek professional counseling if you aren't already. There is so much in life to enjoy.