Baby is sick, hard time getting to sleep?

My LO has had a cold for the past few days. It's slowly getting better, but for the past 3 or 4 nights, he has been EXTREMELY fussy while trying to get to sleep. Not just at night, but at nap time too. He has never had issues falling asleep, and he'll doze then start coughing and wake up and we'll have to start all over again. My question is,,,

if your LO has ever been sick was it hard to get them to sleep? I'm scared this is a permanent thing. I mean, I'll start trying to get him to doze around 1045pm and usually he'll finally pass out at 2am. This is not normal for him at all, and its exhausting to me. This is after trying EVERYTHING in the book. However if you have a suggestion on how to get him to fall asleep, feel free to share it!

ETA: He still STTN, even while sick. When his cough was REAL bad a few days ago he was only sleeping 5 hours (I know I know, thats still wonderful), but now that hes slowly getting better it has increased to 7-8 hours again.