I don't think it's irrational
(and sorry Riri, my response is a bit of a personal rant, discard it if it's not relevant to you)
I may be wrong but I think it is a problem may be that induced by forums .
There are many people who scaremonger about taking insulin. It makes people think that less insulin is better. You fear that you are becoming insulin insensitive or that somehow the extra insulin will cause a problem. There is a feeling that you haven't been 'good enough'
In non diabetic humans the insulin produced varies, we are no different. If you need it, you need it. At some ages, situations, times of the month, illness etc (as you suggest hormones may play a part) you may need a lot more than others. And yes, sometimes everything goes crazy and there seems no rhyme nor reason for changes in sensitivity
If you need it, it is far better to take it than risk high levels and DKA.
I had the opposite fear induced by forums... that of not achieving 'normal' levels and ended up with an HbA1c in the 4s and almost no hypo awareness.