Spotting pre transfer

This is my first FET cycle following successful fresh transfer 5 years ago. I have been on progynova since cd1 and was scanned on Sunday (cd14) to check lining, all was good so started cyclogest (progesterone suppositories) on Sunday evening. I’m now cd16 and due transfer on Friday which will be cd19. Had a very small amount of spotting this morning after bowel movement (tmi I know). It seems to be stopping now. Tried to call clinic but haven’t got through yet.

Has this ever happened to anyone else? Confused as I’m obviously not due for on and meds should be stopping that anyway.