Sleep regression

My son is just over 3 months old. We put him down for bed around 7 ish and he will sleep any where from 4-5 ish hours then wake up. I will feed him etc then I'll lay him back down in his bed (he's completely falling asleep as I'm trying to burp him) and as soon as I lay him down he wakes up and starts to fuss and squirm. As soon as I pick him up and start rocking him he's passed back out. This pattern will repeat until I finally give up and take him back to bed with me just so I can get some sleep! He sleeps great when he's snuggled up next to me. Before however we'd lay him down for bed, he'd wake up to eat and I'd put him back down and he'd continue sleeping in his own bed. So I am not sure why all the sudden he's regressing? Any ideas, tips? Others in the same boat?