My last real period was Oct 13. Of course my partner and I have had unprotected sex a few times since. On Nov 7th I started cramping but lightly spotting for a few days, not enough to fill a pad or tampon. Since about the 12th I've started with nausea, fatigue & frequent urination. My next period wasn't scheduled to start until Nov 15th which obviously hasn't happened. I took a couple of pregnancy test last week and they both were negative. When should I retest?