5 month old screams at night!!

Leila
So I've posted before about my LO not sleeping well but this is out of control. He was such a good sleeper waking up once to eat than going back to sleep. Now,we put him down to sleep his up every 2 hours screaming his head off. He stops when I put in bed with us and shove a nip in his mouth. This is usually the last resort after hours of crying and us walking him around. I don't know what to do. Any advice. And yes, we do a bedtime routine.