Hardest thing I've ever done

I think it's safe to say, that at only 5 days into it, breastfeeding is one of the hardest things I've ever had to do. My baby girl can latch, but a lot of times she doesn't open her moth wide enough so I have to unlatch & re-latch 2-5 times, or when I'm trying to latch her on she'll put her fists in her mouth. My boobs are engorged, they hurt very bad, they leak & my nipples are side and cracking. I sent from an A cup to a C cup so none of my shirts fit. Did I mention how much I leak? I leaked into a bottle it was 3 oz ( my daughter was 3 days old at the time). I feel so stressed about it but I don't want to just quit so soon and not give my baby a chance at breastmilk.