I am glad you got some sleep. Please phone your health visitor/GP today and explain to them what you have told us. I'm no medial expert but my own DS had pain when feeding and was refusing feed and it ended up being silent reflux and suspected cows milk allergy. Prescription formula and medication have helped us but took a while to find a balance. Other things that have helped are:
• Feeding position. Look up feeding positions for reflux. My DS is bottle fed and I feed him at home sat almost bolt upright against a pillow. Keeping them upright helps after a feed helps too.
• Placing a thick book to elevate the moses basket end helped too. Not too much but at a 25% degree angle and I was told that that this was still within safe sleeping guidance.
• Are you breast or bottle feeding? If bottle feeding and it isn't an allergy, using a thicker formula can help the milk stay down. I know people that have had success using a comfort or anti reflux formula but also those that switched to kendamil or hipp organic. Again trial and error as every baby is different.
• Cranial osteopathy and chriopractor can also help too. There will be those that will say it's a waste of time but I think when you're desperate I think any help is beneficial.
• Where is your partner in all this? If they live with you they need to be sharing the load. My partner works two jobs but we still share night wakes (or did, my DS only gets up once a night now usually). On the weekend, we will take it in turns to have a lie in which helps too.
Of course as people say it will pass but however in the meantime there are things that can be done. Please keep on at your GP/health visitor.