Trying to Control Hormones. Need HELP!

So I am 29 weeks pregnant and my hormones have been horrible. I have been so mean to my boyfriend. This is my first pregnancy and I just don't understand the urge to lash out. Last night I wanted him to turn the light off because I really wanted to get some sleep and was finally comfortable. He said he needed them on to work. I asked him again and he again said he needed to finish his work. I lashed out and said some stuff I really wish I could take back. He was really hurt and ended up leaving to his sister's. She called me pissed saying he came over in tears (he's always been on the more sensitive side). She told me not to blame it on my hormones because I still have control over my actions and I had no right to say what I said. I completely agree with her. I had no right to do so. It's just the anger comes so quick and I want to Learn how to control it. He came back this morning but is obviously still hurt about everything. I don't like hurting him. Any advice on how to tackle down these hormones or manage pregnancy anger