Rape and Pregnancy.

Long story short, an older man got me drunk and took advantage of me in a hotel room on November 29th. I later found out I was pregnant. I had a dating scan a few weeks later that put me at 11w4 days. My doctor told me based off of my dating scan I would have conceived on November 6th, and that it was impossible I conceived by the rape. That made me really happy so me and my husband continued with the pregnancy and I am now 26w4d. I still get so scared that the baby is from the rape. My husband still gets scared sometimes too. I don’t know how to heal from it with all these thoughts in the back of my head. I get worried that because I don’t have as big of a belly as most women at this stage, that my ultrasound was off and that it’s actually the rapists baby. If it was I don’t know what I’d do. My husband said he will be here no matter what, but I know it would kill him. Is it possible my scan could be off by that much? My doctor said I would have been 5 weeks already when I was taken advantage of.