HE WONT SLEEP!😓😪

So i have a 7 month old son who is the absolute love of my life. He is always smiling even to strangers but the issue is when its time to sleep... He wont go to sleep unless i rock him to sleep 😳 i dont know what to do at this point. Im going bqck to work next week and im afraid any baby sitter i get will only run away because of that. He wont sleep unless i rock him and i must make sure he is fully asleep before putting him in his crib. Idk what to do anymore i need help! What can i do!?