I have had a similar thing this year,
I have for years been very regular- 28 days to the day, but last year was 29,28,27,45,59,27,45,23,29,30,28
this year have been, 28, 34, 26,27,28, 22,21,40, 24, and am now on day 32 with no sign of anything. (good old iphone app)
am not happy about the shorter cycles though- though menopause meant fewer periods- I am a bit older than you though at 47.
I haven't spoken to the doctor yet, no other particular symptoms so haven't bothered