Why am I such a bitch to my boyfriend when he's sick. I'm mopey, distant and just miserable when he's ill.

Background: 1.) My bf has poor immunity (obviously not his fault) and gets a cold about once a month, this week has been the worst in a while, thought it was the flu considering the massive outbreak recently but he tested negative.

2.) I've been having trouble with social anxiety all my life but it's gotten a bit out of control the last few months. Makes me feel worthless, weak, the whole shpeil, although I don't think it's the reason for my behaviour.

3.) I want to be the perfect girlfriend that's sweet and supportive emotionally, I should say he's not the complaining big baby that apparently men turn into when they don't feel well. He basically doesn't require anything extra of me except for running out for medicine, food, or a bit of cooking, nothing I mind doing, it being easier anxiety wise knowing he needs these things. (Normally I won't go out more than absolutely necessary because I think anyone who sees me instantly hates me, irrational I know but hey social anxiety)

I guess my anxiety does have a role in this because I rely on him for emotional support and reassurance and I don't feel like I can do that while he's sick. Instead I feel like the one that's supposed to be picking up his mood. The harder I try the more frustrated I get and the worse I feel for being upset at him for something he can't control, enter endless destructive negative thought cycle. I know I should just stop whining and get over it but I can't drag myself out of this angry disgusting selfish person that I am when I'm not the center of his attention. I hate myself for not being strong enough to be what I should be when he's not 100%, he's always there for me no matter what even with all the crazy stuff I lay on him and he never gets upset or annoyed. I feel disgusting, like a self centered spoiled child, which I probably am, just wondering what you all think.

TL/DR: Feel like a disgusting spoiled child for not being there emotionally for my boyfriend when he's sick.

Sorry for the length and formatting!