Im 19 weeks and one day pregnant today. My due date is oct. 19 th of this year.is it possible I got pregnant between the 1st and 5th of jan.

It's possible but there's a fairly wide window of time. Are there two (or more) possible fathers?

Yes, it's possible, but if paternity is in question you will need to have a DNA test done after the baby is born.

Yes but my dr did an ultra sound and said I moat likely got pregnant between jan 26 and the 30th.I had sex once on the 2nd then had my period on the tenth then had sex again 3 times after my period and the following month I didn't have a period.

Unfortunately you are going to have to wait until the baby is born for a DNA test.