Frustrating bedtime *ETA

My son nurses to sleep but it doesn't matter when he goes to bed, he's having a had time falling Into a deep sleep.he nurses until he's Zleep. And then I have to hold him for a while until he's RIGHT OUT otherwise the second I go to move him he's wide awake. It's been almost two hours and the second time he's woken up and we have to start the process AGAIN. My back kills from this bad posture already. I'm tired myself and idk what to do. You CANNOT put him to sleep any other way. Tried rocking and humming or singing just fights and squirms. Nothing works. Trust me we've tried.

Idk what else to do. I'm exhausted and frustrated.

Eta: 9 months old.