I certainly would'nt worry about feeling guilty if your sick, at the end of the day, if your not fit to work, theirs really nothing you or anyone can do about it.
In regards to you feeling guilty about everything, i would probably put this down to you having a caring side, theirs nothing wrong whatsoever with this, tho i would say, that some people in life would take advantage of your caring side/guilty feelings etc.
It would be nice if feeling guilty was a common thing, but this day and age this seems less likely, i suspose looking after number one springs to mind, try not to get yourself worked up over feeling guilty etc, your not hurting anyone other than yourself {ie getting worked up over nothing}, lifes to short to worry, try relaxing a bit more, i'm sure your be fine.
Get well soon, and have a nice christmas