Breast feeding and formula feeding

Ashley
So like normal from the delivery till now nothing has gone as planned. I was planning on having a completely natural birth I ended up having to have a emergency C-Section. After that I was not able to have skin to skin contact nor feed within the first few hours. I had been exclusively breast feeding until the fourth day which I suring fed him formula , oh and I also had to stay in the hospital for 5 days because I broke out in a fever, because he had dropped weight by 10 percent. Finally I am home and it's been a week my milk finally came in I have been pumping when I can but God I am so tiered. I've noticed he uses my boob to go to sleep as well my nipples are so sore and chap that I was literally crying last night because it hurt so badly I've been using the Lanolin cream and it helps to and extent. I finally gave him a bottle today which he did fine with then the next feeding I gave him my breast and it felt a lot better. I want to get to exclusively breast feeding even if it's just pumping is it ok if I alternate the formula and breast milk? Will he stop on my breast? Does anyone have advice?