I would think maybe a growth spurt. I do remember very vividly my DS doing the same thing around the same age and also remember the tears that came with it so huge

My DS was a prem bub too and was told by my CHN that you go by actual age for growth spurts and feeding. If you dont already maybe try baby massage, dark room, quiet space. If its something you are happy to consider maybe try expressing some milk and giving him a bottle to give your nipples a break. My DS had bottles in the SCN and breastfeed well too, we never had any trouble with teet confusion. If you dont want to go down the path of bottles, grab yourself some nipple shields, they were a godsend for me.

other than that I'd suggest a sling, and for your partner to take him for 20min or so, and you go and have a bath to help keep you relaxed. He will pick up on mummy feeling frazzled, calmer you are, the better off you all will be. (Though I do know thats easier said then done).

HTH and GL