help with 4 yr old!!!

so I'm at home all alone with my 4 year old all day. she is getting to where she's rebellious, wooping her isn't working she just looks at me and says that didn't hurt which makes me angry and I have to calm myself I don't woop her hard and time outs she just says i hate you and such, I snap at the tiniest things now, I don't mean to, but she won't listen. I'm 16 weeks pregnant and I used to be so patient but not I can't seem to be. any help?