So yea I will also be doing head cannons and this is one of them. This was requested by @Wintersday2. Thank you for reading!
Raph-
Will keep asking you if your okay like every 2 minutes. He really doesn't like seeing you like this. He takes care of you, but is careful of course so he doesn't get sick. He wants to kiss you, but doesn't so he doesn't get sick. Because of this, when you are better, he gives you SO MANY kisses that he was holding back on when you were sick.
Leo-
Despite you being sick, he still gives you kisses hoping it will make you feel better. He doesn't mind if he gets sick because then "you guys can be sick together.", as he says. He makes sure you are okay pretty often and takes care of you. He lends you some Jupiter Jim DVDs to watch when your bored (which is pretty often).
Donnie-
Actually tries to make an antidote sort of thing, even though you are already taking regular medicine. He takes care of you, but definitely refrains from touching you/getting too close to you. He REALLY doesn't want to get sick. Of course, he still cares about you though, obviously. He gives you more affection when you are no longer sick.
Mikey-
He makes sure all the food he gives you tastes extra good. Even though the only thing you really eat while being sick is soup and crackers. Still, he makes sure it's the best soup and crackers you have ever had. He was really worried when he first found out you were sick, but became less freaked out as you slowly got better.
April-
Takes care of you when you need it, but also gives you the privacy you need, while also being careful to not get sick. She sends you funny videos/memes pretty often to cheer you up. (Idk why else to put for this one🥲).