What Causes Light Menstrual Bleeding Along With Brown Spotting?

My period is about two weeks late. The week it was due I had very light pink and then brownish spotting but no other period symptoms. This has never happened before. And I can always calculate the days when my period will arrive. Lately I notice myself using the bathroom more often and urgently, I ve had light headaches and acid reflux and my body feels warmer than usual. Could I be pregnant? My husband and I always use condoms and we are very careful. However I have occasionally noted sperm leaking out the bottom. I did not think this would be enough to worry about, being such a small small amount. Is there another reason my body could be reacting so oddly? Could I have some kind of infection or cancer? Just today my breasts started getting a tiny bit tender. Not hardly enough to note. I haven t been able to sleep comfortably either. Thank you.