Advice needed please

My baby is one week old today. Breastfeeding had been going great. He was born tiny, 5lbs 11oz, and doctor was worried I’d have to supplement to get his birth weight back up, but at 6 days old, he had gained 8 oz in 3 days and was over his birth weight, so he clearly was getting enough from me!

Last night, he started to refuse to latch. Like screaming at the boob, only suckling on the end of my nipple, or latching for a second and then letting go. This goes on for extended periods of time before he eventually gives up and just latches on. However, he dropped his sessions from 20-30 minutes to 10 minutes or less. I’ve tried switching positions, skin to skin before the feed, hand expression before a feed and nothing is working.

Any advice is welcome