Is it forgivable??

I am 10 days away from having my baby and feel like I have zero patience left .I'm so easily irritated and doesn't help that I am under stress financially and physically as I am still working a very physical job so constantly sore and when I stop working it is unpaid leave. So tonight my mother basically told me that my 8 year old daughter doesn't feel close to me because I'm in a nutshell not being a good mom. I got onto her because she told her stepdad she would work on cleaning her room this weekend and did not. So my mom told me I was wrong and should be defending my daughter against my husband because she just a little girl and we are responsible for her room being  clean and she had done nothing wrong. She says all this in front of my daughter!! I got so mad and tried to explain to her that undermining us in front of her is not helpful. She just kept arguing with me to the point that I became this screaming enraged idiot and told her she needed to leave. She refused to leave and kept saying that me screaming was exactly why I was wrong and basically saying I was not being a good mom lately. I admit it got to the point that I was crying screaming cussing and begging her to just leave! I am embarrassed I acted that way, but why would she just keep it going seeing how upset it was getting me?! By the time she finally left I was crying and shaking from rage!!! I know that she is going to tell my dad I cussed her and threw her out and I'm embarrassed I did that, but in my condition and emotional state I also feel like she wrong to get me to that point in the first place. What do you think? Am I just horrible, or are hormones to blame?