Hi
I've had this issue and sometimes for me a dose change triggers a stinker and it settles. I have used quite regularly those baby scan places to check my endo lining, they are cheap and really friendly and this puts my mind at rest.
I'd wait and see if it settles provided you are on a safe dose of P. Also I take tranexamic acid - this can be combined with ibuprofen for max effect (or mefanamic acid if you want to wheel out the big guns) for the first three days of your period, it really does help.
Also, in addition to the above, I also take medicinal herbs, I drink Yarrow Tea all month, and then I take yarrow, shepherd's purse and lady's mantle tincture through my period, also really does help. Discussed with my gynae who was a) fascinated and b) approving, so all with a doctor's blessing.
I find being on a routine really helps, I've also started adding the odd dose of P in week two (as E starts to sharply rise) as according to the BMS Menopause guidelines some women try a long cycle P, 21 days from Day 7 controls bleeding (you can google this). I'm quite sensitive to P so I found that much P made me feel bad, so I'm sneaking up on my hormones by having say two dose of P in week two, then 14 doses continuously from day 12, so I'm getting 16 - 17 doses P per cycle. This has helped enormously.
I am utterly intolerant to synthetic P so for me IUD or pills is last resort and so far I've managed to find a fuel mixture that works for me. I take my utro vaginally too, seems to work better that way for bleeding.
GS
x