I would just like to add one more voice to the "do what you think is best, and don't feel any guilt" group of voices.
I firmly believe and advocate breastfeeding, but never in a million years would I criticize you or anyone else for switching to formula for either your health or sanity or the baby's.
My son had terrible reflux and had eczema, but the eczema wasn't really too bad (clears up with lotion daily, minimal bathing, and it helped when I cut dairy out while BFing). The reflux he grew out of (the 3 week to 5 month period of age was the worst....) But if I had thought for a moment that stopping BFing would've fixed the problems, I'd have done it in a heartbeat.
It's okay to mourn having to stop breastfeeding, though. It sounds like something you wanted to do with/for your baby, and that that might not work out... Sometimes we have to mourn the demise of our hopes in order to heal and move on.