Hello ma'am and welcome.
There are many contributing factors and conditions for such a presentation and I would not assume endometriosis
without elaborate evaluation.
The fact that you had a previously normal menstrual cycle states that therw could in fact be some abnormality present which needs to be diagnosed and accordingly treated. For this reason I would strongly advise you to visit your doctor and get treated before you start trying for conception.
A few possibilities include hormonal
imbalances, fibroid uterus
, ovarian cycts, endometriosis, etc.
Hope this helps.