I started having alternately light and normal periods. then no period for a number of months. now i have a period, for a number of weeks, that won't stop. i am 46. i sometimes feel hot for no reason. is it safe to assume that this is (peri)menopause?

True menopause is the complete cessation of hormone production from ovaries, on average about age 54 . The preceding years have variation in estrogen production, which is much higher on occasion, and without regular ovulation, which stops regular periods. When the estrogen drops from a high point to near zero, symptoms ("hot flashes", sustained bleeding, etc.) occur.

Your speculation is right on! Anovulatory cycles are common at the start and cessation of menstrual periods. They can result in prolonged bleeding, flushing, and, unfortunately, unexpected pregnancy. See a trusted gynecologist for examination and counseling.