Had chocolate cyst laparoscopy done 3 months back, was on gnrh hormoneinjection.when can i have my periods as it is already 1 1/2 months now

Typically 3+ mo.: Typically when you receive gnrh injections, such as lupron, (leuprolide) they are effective for 3 months at a time. So, you'd be more than 3 months before you'd start to have a menstrual cycle. So, i would say at least 4 months before your first period.

Endometriosis: Sounds like the periods should be returning soon, like within 2 weeks.