Breastfeeding Problems

I was prepared to give up breastfeeding but this week my little boom boom has had some major difficulty with formula. I have been supplementing more now that I'm back to work & cant pump as often. This weekend he's had major diarrhea! His little bum is raw & he 💩S every time he gets a bottle. I tried nursing but baby gets frustrated bc there's nothing coming out. I'm only pumping 1oz per breast. I'm so sad frustrated & discouraged.