Sleep help!

Maddy

My 7 month old has been sleeping through the night since beginning of Sept. then the last three weeks he has been sick off and on and wakes 2-3 times a night. He is well now and has been for over a week. Still waking multiple times and taking an hour to go back down. Tried to let him cry it out last night after over a hour of trying to get him back down. He got so stressed he threw up everywhere. I just don’t know what to do! Any suggestions?