That all seems a bit back to front!
Utrogestan is supposed to keep the lining thin, not cause bleeding .
With that highish patch the advice now is to consider 200mgs a day of Utrogestan (not 300mgs.)
You definitely should not drop back to 100mgs.
You really need a scan.
The increased dose can't have provoked a bleed- it's supposed to do the opposite.
It looks from what you have said that your lining has built up on the previous dose and it's shedding.
So, you need a scan and then a review of what next. You should call your dr and arrange an appt and in theory you should be fast-tracked for a scan within 2 weeks.
But meanwhile stick to 300mgs.
If you have a thickened lining you may need to use Norethisterone for a few months to thin it.
75mgs is also a high dose for someone of 63- is there a reason why you are on that high dose? have you crept up from a lower dose like 37mcgs, 50 mcgs?