breastfeeding

This is my second child...I breastfed my first daughter for about 10 weeks and was miserable. Now my second daughter is here and 1 week old and I am already miserable. In pain, already have had mastitis, no sleep. She wants to eat every hour and my sanity is slowly slipping. Am I terrible that I want to switch to formula already? I am having trouble with being the only one she can rely on to feed. My husband wants to help but can't do much. pumping is an option but another thing I'm struggling with is knowing if what I'm eating making my little one fuss or upset. Having to monitor every single meal and drink that goes into my body gives me extreme anxiety.   I feel like a terrible mother...thoughts please?