Hi.. I Have Had A Period From The 4th To

Hi.. I have had a period from the 4th to the 7th of last month, then had another for only two days eleven days after. Shortly after I came down with the mumps for two weeks. Now that I am better I was expecting my period (judging by the two day period I had) the 14th of October. It is now the 21st and I have no period and a few classic pregnancy symptoms. I also have been having unprotected sex trying to conceive. Is it possible I am pregnant or can an illness throw off a period by this much? My periods have never been more than 4 days off. Thank you