Help!!!

I don't think I can do this anymore. My bf is always mad at me for some stupid reason. He said the reason I haven't got pregnant is because the way I treat his daughter. I don't do anything wrong. Someone has to step up and be a parent cuz he won't, he lets her get away with everything. The mom gave me permission to discipline her daughter if she is acting up. We just got into an argument over that and I started trying to dig into my arms, I started searching for sleeping pills. All I want to do is sleep... I forgot to take my medication today...