Can you get this lot down in writing with a friendly manager, so it goes on your record? I can understand your frustration. Do you have doctors notes etc. confirming your illness? If not, perhaps it's worth enquiring with management whether getting them would help your case in the event of another illness? The only justification I can think of for such a policy is that too many people are pulling sickies - in which case a doctor's note ought to verify that you're not, and should help your case should it go to a tribunal. Not that I think doctors notes are in general a good use of doctors time, but I think these circumstances justify it.