Am I to late?

So my milk supply dropped drastically since I’ve gone back to work and it made me switch to formula. I’ve been mixing half breast milk with formula for the last two or three weeks now (my freezer stash) and my pumping sessions dropped from 4-5 times a day to maybe 1-2 if that. I decided to stop breastfeeding and dry up but every time I get full I start to cry and try to make breastfeeding work. I feel like now my supply is gone even though I can still pump like 2oz from both side in a 15 minute session and I decided to give it one more time before I fully quit. Is it too late to rebuild that supply? Is there something that can help gain back? Ever since my daughter was born I’ve never been able to pump more than 4oz between both breasts in a pumping session anyway so maybe it hasn’t changed too much or maybe I wasn’t producing enough in the beginning? I just need opinions please. I feel like this is emotionally draining me and making me depressed. I just want to breastfeed but I know I destroyed my chances and I just want advice on what to do...