I can’t do this

How common is depression during pregnancy in all reality? I am 18 weeks along and just feeling so down in the dumps that it’s ridiculous. I can barely get out of bed, I have no motivation to do anything. I do the bare minimum and I just feel completely worthless. I’ve been going through a lot. My boyfriend and I broke up right after I found out I was pregnant and he has severe mental issues that have caused him to abuse me mentally and emotionally for months. So now I’m facing doing this all on my own. I’m about to be in my own place paying rent and all bills by myself with no help other than a slight bit that my mother can offer me after the baby is born, child support will be an option, but not until the baby is a little older just due to the fact that I can’t let him take my baby from me for visitation while I’m breast feeding, he’s a very manipulative person and would do anything he could to hurt me. I have a great job that I actually really love working at, but for some reason I’ve lost all motivation to even get up in the mornings to go. I’m late a lot, and have called out a bit also. I just don’t know what to do or how to beat feeling like this. I feel like a complete failure and I can’t stand it. I just want my motivation back. I don’t know how to get it back. I know I need to probably talk to my doctor about this also, I have an appt next week I’m going to bring this up if I get some time alone with him in the room (my mother will be there). Does anyone have any advice or anything at all? I’m just tired of hysterically crying at night when I’m alone.