Last bottle of breast milk 😭

I've had a helluva time breast feeding. Apparently I have IGT. Anyhow I was able to pump and supplement for the past four months but now I'm back to work, my milk is totally drying up. I pumped six ounces about a week ago (down from 11-12 daily) and over the last three days I went from six to four to three. I hate the way this makes me feel. I want what's best for my baby (yes I know fed is best but breast is better than formula). I don't know why but I fee like I'm failing him and I really wish I could keep pumping enough for him.Â