Can I give my 15 month old melatonin to help with restless nights due to teething?

I am currently 15 weeks pregnant, and he won’t sleep in his crib for long periods of time without me comforting him. He will sleep all night long if he’s sleeping in the middle between his dad and I, but it’s putting a strain on our sleep and relationship, and it’s getting so hard with me being pregnant because he’s a kicker. I’m so worried he will kick the belly and somehow hurt the baby. Does anyone have any advice? He used to sleep SO WELL in his crib from about 8pm to 7:30am. Without ever waking. Now he wakes two hours after I put him down for bed.