Two weeks ago was considered, by glow, as my fertile week. My husband and I had sex on the last day of my period and two days at the beginning of my fertile week. I was experiencing nausea off and on recently accompanied with moderate cramping and pressure really low in my abdomin. I was also experiencing uncomfortable lower back pain between my hips. I thought I was experiencing implantation bleeding, but it lasted 4 days (not supposed to get my period for another 12 days). Now my boobs are feeling tender and heavy.  I'm on the pill, by I never get these side effects and syptoms.