losing my mind

if you aren't going to read it all please move on I need advice not judgement or criticism.... ever since my little girl was born (she's 13 months now) I just can't handle it anytime she screams I scream my head off at her back then it wasn't as bad because I would try everything and didn't know what to do and eventually would just cry but as she got older and she did the same temper tantrums and screaming and would have the thought of just shaking her, throwing her, hitting her anything just so she would be quiet (LET ME NOTE I HAVE NEVER HURT HER OR LAID A HAND ON HER) now it's come back where I wanna do those things all over again because she just screams and throws her temper tantrums and it's even worse sense I'm pregnant again ... I'm still tresses out of my mind and my fiance is like we'll just spank her but I can't because I'm so mad that I'll end up hurting her so I just put her in her crib and let her scream it out until I can calm which the longest it has taken like 2 hours idk what to do or how to calm down .... I know I'm not a good mom when I can't even calm down my child without having thought of wanting to hurt her