How do I save my relationship for my crazy pregnancy hormones?

I am 20 weeks aIong and I snap at my fiance for nothing or over very little all on a regular basis and we fight about it and I try to control myself but I feel like I can't. It got to where we were fighting about it all the time and he would get upset and hurt and yell at me for talking to him like that so now when he gets the slightest amount upset I cry near hysterically. Neither of us feel that I am being as supportive of his emotions as I need to be.but I try to ask him how he is doing and i think he isnt telling me much so that I am not more stressed out. but i dont know how to support him if he isn't telling me what is happening for him. I feel like I am pushing him away and that I can't openly communicate with him with out crying and being a crazy pregnant women so my needs aren't being met either and that makes it all more intense.