I went through a similar process and felt terrible about it, throughout the rather long sequence of warning and disciplinary meetings that this shite policy triggered. I was on good terms with my manager and have no reasons to believe that anyone was questioning whether the absence was genuine. It was just the policy, and unavoidable at that.
In my case I was off sick for a week, then worked from home, then my chest infection got worse and I was signed off by GP again for a few days. The policy (which I have never heard of prior to this) was 10 days absence in a calendar year, or 4 separate absences in a calendar year.
The resolution was to reduce my sick allowance for the next 6 months by half, and if I stay within those absence limits then that's that; otherwise stage 2 disciplinary meetings, further investigation etc. It was insulting - telling a person who has just recovered that they are no longer 'allowed' to be off sick is insulting; if anything, someone who's just recovered from an illness needs to be more careful, and look after themselves more, not less. But I've not been off sick in the next 6 months, and after a few check-up meetings the matter was forgotten.
I was in banking so the policy was created in response to call center staff skyving. I wasn't in the call center but it was blanket policy for everyone. I think this policy is shamefully wrong.
I would second the PP advice to not try to be nice or maintain a conversation, but just factually, briefly and to the point answer all the questions, and get it over and done with. Fingers crossed all will be fine.