Nothing is working !!! LO is 15 months old

Alyssa

My LO is such a terrible sleeper. He has like separation anxiety or something at night. Idk he constantly wakes up and wants to be rocked back to sleep. As soon as you place him down in the crib he hysterically cries. Anyone else in the same boat? Or were you in the same boat and now your LO sleeps decent? Any advice etc.