Hi, Im 18 years old. I'm 16 days late. Before my menstruation is irregular, once every 2 months but when me and my boyfriend started sex, I got my menstruation every month. My last normal menstruation cycle was 0ct 2 and we did sex by oct 15. Just 1 time sex ( 1 round ) and haven't done it again. We do withdrawal. Im 16 days late. Im in stress the whole month, don't have a tender breast, I lose weight and just now, after I woke up, I have some blood discharge, little discharge actually then became brown. What's the brown discharge? Anyone knows what's happening to me?

It might be your period getting ready to start... might be pregnancy... might be hormone fluctuations and you will have another irregular period.

Best thing would be to try a pregnancy test.