ladies ideas!? I am 21 days late. we had sex with in my ovulation time. Dec around 17th and 25th.…

ladies ideas!? I am 21 days late. we had sex with in my ovulation time. Dec around 17th and 25th. all negative urine tests I thought I seen a positive but I guess not. anyway and a negative blood test (on the 14th of jan). I am having SI joint issues so was on cymbalta got off about 3 weeks ago and currently on a narco. but dr said should not have an effect on my periods. I go back in about a week for another blood test. any one ever have issues getting a positive after this long?