Keep feeding him. You need to feed through cracked nipples, I'm afraid. We have all been there - you need to work through it. Get Lansinoh and apply copious amounts before and after feeding. Do not give formula unless it is obvious the baby isn't getting anything. Get yourself and your baby into bed, clothes off and feed feed feed. If you can, pump for 15 minutes following mos feeds and freeze any milk gained. You're aiming for feeds from the breast and not expressed milk at the minute. Increase your fluid intake, watch the caffeine and make sure you have plenty to eat yourself. Push for a referral for the TT. Milk on the tongue following a feed is normal but ge it checked out.