Moms with experience please help me

I feel horrible, I have been beating myself up ALL day! My 8 month old son wakes up super early in the morning while I'm still recouping from work, and he's a busy body! I was breastfeeding him and fell asleep which I usually do. Next thing I know I heard a loud thump and he wasn't on the bed!!!!!!! He was on the floor on his back crying! I screamed & picked him up! He cried for like a minute & a half and then was fine and continued to play and laugh. This was a big fall, like 2 feet & he fell straight on his back on the hard wood floor... I feel so terrible... Like if I had fell that hard on my back I would probably be aching for a whole month! He started crawling around and playing again. He didn't have any swelling, his pupils were normal, no vomitting. But when I picked him up after work his grandparents noticed he'd been jumping in his sleep and I noticed his breathing has been weird like hiccups every now & then. I have tried to wake him up but he's sleeping pretty deep.... I'm scared to go to bed....  What should I do ):