Are irregular periods a sign of early menopause?

My periods have been pretty regular most of my life and aside from endometriosis have not had major issues. I'm 39 and for the past three months my periods have been irregular. They've been either three weeks early or then two weeks late. Now it looks like it will be two weeks early this month. I was just curious if this could be a sign of menopause. I haven't gone to the doctor because I don't have health insurance at the moment. Any insights would be appreciated. Thanks!