I don't really know where to put this. So sorry if it's wrong.

Long story short my mom married my dad before I was born, and he became an addict after I was born, & a hustler. My dad ended up getting locked up for murder when I was 3. My parents obviously divorced. Well I was so excited to find out my mom found a man when I was 11-12 years old. He also has a son. I never had a brother, only a sister so I was that much more excited. They ended up getting married, & they've been together for about 8 years now. I never really had a dad so I was happy to have a "normal" family again. Well I got home late lastnight, around 10:30 and my step dads car was gone. I thought maybe it was getting fixed or something, & he was gonnna drive my moms to work. Come to find my mom bawling this morning, the bastard was cheating on her, WITH SEVERAL WOMEN. I'm sad, I'm broken for her. She packed up his shit and he's staying with his parents. I guess, idk how I'm gonna adjust to this. I mean, I was moving out of the house this upcoming weekend. I can't leave my mom here alone. I'm the last kid living here. But I have a baby coming in just 10 weeks. My mama is going to the doctor to get some sleeping pills, she hasn't slept since yesterday. Any advice? I'm so sad.