I'm ill. I've run myself down by doing too much overtime at work, as well doing gigs in-between and only getting 5 hours sleep before repeating the whole sorry cycle again.
This annoys me as I often boast to my wife about how excellent my immune system is, brags that will now no doubt fall on deaf ears. If immune systems were rated like hotels, mine would definitely have been one of those Dubai hotels that break the mold by getting seven stars because they have private butlers for every room. But now, even if my immune system did have a private butler, he'd likely sign off sick for a week due to exhaustion.
This reminds me of that Greek myth about the man who kissed his lover's head, and she asked him not to because "my hair is gross from the London underground," and he continued to do it anyway because he thought his immunse system was invincible. He was ill for a fortnight.*