Any ideas?

Allie

So I am now 2 days late and usually my periods are pretty regular with a few days here and there. I had unprotected sex last month around ovulation. Last week, I had the common PMS symptoms, like cramping, back ache, tired. I was also spotting a little and had mild brown discharge for about 5 days or so on and off. Pregnancy tests are all negative as of now. Any ideas what this could be? Any advice please!