Help please

Alexus

My 6 month old wants to be on my nipple 24/7 but most of the time it’s not to eat it’s just to literally have something in his mouth he will scream and scream and scream like he has to have something in his mouth. He sticks his tongue out and acts like he needs to chew on something and screams because it’s not my nipple . His doctor claims he is not teething but last night he was screaming nun stop last night and putting the blanket in his mouth to chew on like I’m so lost idk what is the problem .