Thanks for the query to H.C.M. Forum. Endometrial cyst
removed but you didn't mention the name of operation and part which operated as endometrium is an integral part of uterus
and bleeding sheds from uterus .
In my opinion get in an ultrasound
of uterus as well ovaries ( for cyst ) and consult either your operating surgeon or another gynecologist and get his opinion as physical examination is very important in this case.
Get in blood for FSH/ LH ratio ( if any alteration).
Sometimes I have noted that cyst reoccur so consider this point also.