I hope the breakthrough bleeding settles. The fibroid may not be helping. Good luck with the meno specialist.
I used to have breakthrough bleeding problems when I first started on the contraceptive pill many years ago and I have never worked out the whys and wherefores of how it happened - I just got prescribed a bog standard pill by a rubbish GP and it was never a problem again with any other pills I took

Since then, I have read that it can be the wrong sort of progestogen, not enough progestogen, too much, or even not enough oestrogen.

I was going to ask for oestrogel + uterogestan but since I also had the hurdle of having had problems with the nurse that wants me off hrt I just asked to change from the femoston 2/10 to the conti 1/5 as I know it is likely to work for so I wouldn't have to keep trying to get appointments with the Right Doctor.
I have read that breakthrough bleeding is not unusual to start with though.
Just to add, I have never had any problem getting femoston 2/10 - it seems less popular.