Hello there, thanks for writing in. If you meant blood clots when you said chunks, it means you must be bleeding more than average during your periods. Endometriosis is known to progress and can give rise to menstrual cramping and excessive bleeding. You must also know that adenomyosis ( endometrial tissue inside uterine muscular wall ), a similar entity like endometriosis can co exist and can lead to your symptoms. While adenomyosis can be easily diagnosed by an ultrasound scan, endometriosis may require a laparoscopy ( key whole procedure ) for its diagnosis and treatment. As a first step, I suggest you get a transvaginal ultrasound scan to look for possible endometrioma, adenomyosis, any fibroids ( can rarely cause cramps but does lead to heavy bleeding ) and endometrial thickness ( thick endometrium can cause excessive vaginal bleeding ). You can take tab.mefenamic acid which can reduce menstrual cramping and bleeding for symptomatic relief. Do schedule an appointment with your OB/ GYN for further evaluation and appropriate treatment.