HELP! I've turned my baby into the worst sleeper in America!

I have a 18 lb 5 month old & I have turned him into the worst sleeper EVER! He needs to be rocked to sleep AND held. I made the mistake of having him sleep in a rock n play for the first month or two & now he cannot sleep unless his feet are all the way propped up. My back hurts. I can't do it anymore & I can't keep almost peeing on myself because I'm holding it too long BECAUSE he wakes up every time he gets put down. I KNOW IT'S MY FAULT. I did this. LOL but someone plz help me fix it!!!!!!!!!