Day 4 no period, negative test

Annie
tested like six times since expected menstrual cycle. Always regular (28 days). Hubby and I were intimate twice in the last three weeks with ejaculation occuring. I wasn't fertile nor ovulating. Having horrid headaches and nausea everyday around 4 pm til I fall asleep. Breaststroke are tender, but not more so than usual during period. Feeling frustrated.