I m two weeks late for the first time in my life, my husband and I are TTC, so we became more and more excited each day. The day after mt missed period I took a digital test-negative, called my doctor and they said wait a week. I used EPT this time for three days in a row, all negative. I went to have an ultrasound due to some very minimal spotting, pelvic and back pain after I was 10 days late. My endometrium is 1.32cm thick,but no mention of a sac was in the report. Just measurements of my ovaries and endometrium. The following day they did a blood test, also negative, and prescribed provera. I m afraid to take it, since we really want to be pregnant. Is there any chance the sac just couldn t be visualized yet and my HCG levels are too low to be detected?