Here to vent about work

I just started a new job. I have a job already and was hoping to make both work, but told restaurant A (new place) they would be my priority. They started scheduling me for training right away, and for the most part I was able to drop shifts I already had scheduled at restaurant B. Yesterday unfortunately I wasn’t able to get my shift covered, so (unfortunately, not proud) I lied and said the girl that was taking my shift called in sick, and I had just found out about 20-30 minutes ago. They were mad I had given such short notice (technically an hour before the shift), but 1. The restaurant doesn’t open until afternoon, and from my story, I had only just been screwed over myself. GM said it was unacceptable and we won’t be doing this every week, and I need to figure out where I want to work. I agreed and said I wanted to work there. I also said I would feel way worse if it weren’t a training shift, and I’d be doing more in my power (despite already doing all that I could) if I actually had a section (I’m a sever), and he said he had given me a section that night, despite me only having two training shifts… The next day, the other manager texts me saying my shift has been cancelled for the evening, and to discuss it with the GM on Tuesday 🤦‍♀️ I think I’m getting fired, but if I’m not, idk if I even want to work there after all the red flags I’ve seen so far, but I’ve been so excited to work there. I think I did the right thing by showing them I’m not the type of person to screw my work over, and I think he was lying about me having my own tables to make me feel bad. Maybe it’s for the best this happened; after that phone call yesterday with restaurant A, I was planning on giving restaurant B my resignation tomorrow.