Somebody help 😭

My little boy is 7 months & has decided as of Monday week that he absolutely does not want to go to sleep. He had his 16 week vaccinations on the Monday (we had to delay due to being away etc) & ever since, he just will not switch off. We haven't changed anything - he has his usual bath etc & as soon as I put him down in his cot he starts waving his arms expecting to be picked up again. He used to settle himself if I lay him on his side but now he goes rigid & yells if I try to turn him. I leave him babbling for a bit then he starts crying so I go back to comfort etc & after a while he ends up getting so cross that he isn't being picked up he cries to the point of choking & even being sick 😢 I don't like to get him out to play again as I feel it's confusing & I'll have to start all over again, but I really don't know what to do now 🤷 he's obviously super tired, but won't stop kicking his legs & just wriggling around - he'll drop off for 30 seconds then he wakes up again & cries & kicks. When he does go off, he has about an hour or 2 then wakes up like he's had a nap & won't go back to sleep for another couple of hours (by which time it's midnight) it's like he's suddenly terrified of going to sleep - if I stick around in his room he wants picking up, if I go he yells....I'm so exhausted & dread trying to get him to sleep now 😞 sorry for the rant...