Lashing out

I love my boyfriend so much he’s great he’s such a good bf and dad always getting me what I’m craving, giving me massages, making sure I’m okay he’s amazing but I feel like I’m hard on him I get mad and irritated so fast I be lashing out or just staying quiet sometimes I feel like it’s out of my control that I feel that way but then I just feel like I’m being a rude and I should be able to control myself. I feel like an asshole most of the time I’ve heard of some girls that also feel bad because they have mood swings and lash out on their partner because of hormones and stuff because our bodies are changing. My bf is good at not lashing out on me or giving an attitude when I’m being stubborn but I don’t know how to control that he deserves to be treated better I wasn’t really like this before I got pregnant. Does anyone have any tips or have a better explanation as to why I’m so stubborn and hard to deal with?🙁