I hear you, MT, and I just happen to have had twice as many sick days last year than I ever had in any year prior, all due to illness or injury that I could have done nothing about, but unfortunately a company is not required to go through the reasons for each sick day. They are entitled to retain their most reliable staff and this is how they do it.
If you've only had 'several' days off in two years (assuming you're a UK EZY pilot) then I wouldn't think you've got much to worry about. How's your conduct been?!