Don’t worry, literally every one of us who has stepped in a gym has done this at some point. It’s a rite of passage of sorts.

If you managed 3 reps on 85 I’d say stick around the 80-85 range. You probably want to stick with a weight where you can do around 3-5 reps with. Once you can do 5/6, go up.

As others have said, get your diet right and don’t put the collars on when you’re lifting alone