Breast milk vs. formula

Alex recently started to drink formula, shortly after her dehydration. Prior to that she refused everything but breast milk. I'm relieved that she took the formula.
I persevered and got her to start drinking formula with a cup. She happily takes it from a bottle ever since. It's a good thing because I know for a fact that she wasn't getting enough from my breast.
I somehow feel guilty at times because of all the hype about breastfeeding and how it's the best option for baby. I always wanted to breastfeed her for as long as possible, hopefully until she was at least one. Although Alex still gets all the milk I have, we do supplement with formula a couple times a day.
On the bright side, I worry much less; I don't worry about wasted /spilled breast milk, I don't worry about Alex getting enough to eat, I don't worry about her weight gain, I don't worry about her getting dehydrated.