When does it get better ? 🥺

I am a single mom of one. My baby father went on his little journey to Atlanta then Florida. My daughter is 18 months & is driving me CRAZY ! The tantrums , the hitting , the telling me no , the crying , pouring & pulling out everything is making me really depressed & stressed. I don’t want to yell at her but sometimes I do. I definitely don’t want to hit her. Idk what to do I’m so frustrated. I do everything by myself while he is living his best life and the only thing my family tells me is “ it’s gonna get better” or “ you only have one child idk what you be stressed about” my daughter is difficult it’s her way or no way & she currently have a small cold so everything I said she does above is worse 🥺 please someone tell me what age does it REALLY get better or do it get better at all ? What should I do ? Sometimes I feel like giving up 😔 I yelled at her and I just broke down. Being a mom is so hard. My daughter have been difficult since she was born she makes it so hard for me 😢