Won’t go back to sleep

Juniper

My son used to sleep great. But now I’m currently on hour two of getting him to fall back asleep. He seems gassy (gave him drops and all the rest). I fed him. I’m at a loss. I’m by myself tonight and I can’t do this every night. What changed, why won’t he go to sleep anymore? He falls asleep on me, he transfers, and then within a few minutes is crying. I’m currently letting him cry because I’m exhausted. But it’s so sad.