hayover
the congestion and fatigue you feel the day after you've suffered hayfever. i.e you technically aren't as bad as the day before, but you still aren't 100% either.
non-hayfever sufferer - "come on! you had hayfever yesterday you should be over it. lets go out!"
hayfever sufferer - "no thanks, i still have a killer hayover"
hayfever sufferer - "no thanks, i still have a killer hayover"