My LMP was 22nd November and I had unprotected sex (one night stand) 4th December. We were as unprotected as it can get, he ejaculated inside me 3 times. My next period would have been due 19th December. I took 2 tests 24 hours apart 21st and 22nd December, both said 2-3 weeks pregnant which would be 4-5 weeks from my LMP. I had pretty bad cramping a couple of days before my period was due in December and I put this down to implantation. So far this all seems pretty straight forward, however..... I had sex with someone else 13th November and I keep thinking what if the baby is his when all along I have assumed it's not? This was still unprotected but no ejaculation. I did a pregnancy test 11th december (4 weeks from 13th November) and it was negative, too early to pick up from 4th December but a higher chance to be positive from 13th November. At my scan on 15th Feb they dated me as 13 weeks but it was only 12+1 from my LMP. Midwife dated my due date as 28th august, scan dated me as 23rd august. Am I being completely neurotic?