Please Help! 15 days late.

15 days late, negative pregnancy tests, I did travel out of the U.S and I did come back jet lag. I was supposed to get my period the day after I came back from my trip. I do have un protected sex and use the " pull out method ". I do feel nauseous, mostly at night, but I do not vomit. ( I have many symptoms of the stomach virus though ) And I have noticed my sex drive is higher. No spotting or discharge. No pregnancy symptoms other than being nauseous and missed period ( and higher sex drive if that is one ). What do you guys think?