Struggling to manage priorities, meet deadlines

I’m working for a small company and have been here just under a year. My department and position have very high turnover due to my horrible manager and the high stress nature of the job.

A little over three months ago I became team lead since I was the only one left. I’ve had to train two new people on unclear content guidelines, develop documentation, develop internal processes, deal with quality issues on our deliverables that I have little control of, learn to manage a department and confusing timelines, and go through the busy season for the first time.

I’m trying to manage quality assurance and priorities but I’m falling behind and my boss is angry. Since we’re no longer understaffed he expects that everything should be perfect now and no overtime should be required.

I’m trying to CYA for myself and my team but I’m overwhelmed and feel like I have no one to turn to. I’m not sure if this is the right place to post this, but I don’t know what to do.

We communicate over Teams and email mostly so I feel like things are documented, but I feel like I’m killing myself and I’m still failing.