Any ideas?

Hey ladies, my last period was on September 5th. Exactly a month after (October 5), I was rushed to the ER because of a kidney infection. They had to get a CT scan to see if I had kidney stones, but because of radiation they tested if I was pregnant first and it was NEGATIVE. Fast forward to November and I still haven’t gotten my period since the last one from September so I decided to take a pregnancy test and it was a very strong POSITIVE. I took another test and it was another strong positive line, even stronger than the control line. I was very surprised. This was two months after my last period. Before my period in September, I skipped two months and I was always regular before that, but now I think I may be irregular and it’s confusing to me how far along I might be. I know it’s either really early or maybe a month? I’m not showing at all but I feel nauseous sometimes. Could I have been pregnant when they CT scanned me even though it showed negative at the time? I have an OB-Gyne appointment at the end of the month but I’m quite worried.