My Husband And I Are Trying To Get Pregnant. We

My husband and I are trying to get pregnant. We have had intercourse 10 of the 25 days mid cycle. I had a few days of nausea, few days of breast tenderness, and was two days late to my period. I am never late and have a very set period schedule. I say I was two days late because I am now having a very light period with lots of cramps and lower back pain. I never have lower back pain. I also took 8 pregnancy tests from 5 days prior to my missed period, up to two days late, and all negative. This would have been my second child and I had no bleeding and a very clear positive pregnancy test with my first child. I am wondering if I may still be pregnant even with a very light period and all of the symptoms I am having, yet a negative test.