Aside from the current bleeding you are having, if you are only very early peri-menopause and your doc has advised you to start the whole HRT cycle randomly ie mid cycle, then this may cause everything to go out of sync. If you were mid cycle then it would have been better to start the gel and provera together, because during the second part of your cycle is when you produce your own progesterone after ovulation.
The instructions for the gel don't actually provide instructions for your scenario ie starting HRT when still early peri-menopause with pretty regular periods but slightly variable cycle length starting to happen. However they do say start at the end of the therapeutic cycle if you are already on other HRT. The cycle starts with Day 1 being the first day of the bleed and then once you've started it just continues with a 28 day cycle.
No-one can say why you have started bleeding early; it could just be due to peri-menopausal cyclical changes, but that being the case in your position I would count the first day of your current bleed as Day 1 and then start the Provera, and hope that you then get another withdrawal bleed partly due to the Provera and also your own ovulation, if you see what I mean? However if you want to go by your doc's instructions then why not try it and see what happens - ie start taking the Provera on Day15 as instructed?
As always though, if the bleeding really worries you then do consult your doc. Hope all goes well!
Have you read this article?
https://www.menopausematters.co.uk/magazine/pdf/Article%20-%20Perils%20of%20the%20Perimenopause.pdfAlso there is information about bleeding on this website on the main menu....
Hurdity x