Took a break

So we took a break a couple months back, and we decided to try again in February. January, I have been tracking to be better prepared, but I don't know if I am sick or pregnant? Why I am confused is because we only BD once this month on January 1st (yup, we brought in the new year with a Big Bang. I know so busted!!), but AF came January 9-12. So I can't be pregnant. I did some research, and now I am confused. On other forums women have said it is possible to conceive a week or even days leading up to AF, especially if you have irregular periods. True not true? I'm not sure, but I do have irregular visits. Though, I could be sick. I work with kids, and on Friday one kid threw up, which I happen to have his younger brother in my class and I am pretty sure he didn't feel good neither on Friday. He usually eats like a champ, but he was refusing! So I could be sick too...