Got normal period last month havent been sexually active since before last period and now lighter period this month what could this mean?

Light period?: If your "light bleeding" started before you would normally have expected the "next period" to begin, and pregnancy is possible, obtain a serum HCG test to be certain you are not pregnant. Sometimes "light bleeding" can occur with twin ovulations, (b/c the estrogen from two follicles is much higher). If the bleeding continues, see your gyn for testing.