Help and advice needed... Please!!!

So I'm 19 weeks, almost 20 weeks pregnant and I think I've reached my emotional stage (Praying it's just a stage that is!!!!). I work as a production manager for a company that is just starting out so it was already extremely stressful and now for the last two weeks in have been breaking down almost every single day. I need this job but I can not seem to handle it at this moment. It doesn't help that my sister is my manager so when I lose my control, I end up taking it out on her. I feel like I'm losing my mind!!! And I'm tired of crying all the time!!! My baby doesn't deserve that and I should be so happy about her but can't get control lately. Any advice would be greatly appreciated.