Sleep regression?

My son just turned 3 months. And went through a huge grow spurt, now I think he is in a sleep regression. What do I do??? He normally sleeps in his bassinet next to me but now everytime I put him down, he wakes up and cries. I try giving him his pacifier but most of the time he refuses it and screams. I don’t know what to do. I’ve been co-sleep after 6am cause I’m too tired to continue trying to put him in the bassinet. But I don’t want to continue to co-sleep (it scares me a lot). Anyway, I’m so tired, he isn’t really napping and not sleeping well at night. Any advice or tips please.