Any help or advice?

Hey y'all I'm looking for any help or advice here's my situation, last period began June 28 where as I had unprotected sex july 11 week of ovulation and while in Alaska on vacation I was sick after every meal and had one day of brown spotting when I got home I expected period to start on August 28, today being almost 21 days late and ladt time I tested 4 days ago all test have said negative.i have a dr apt for the 28 looking for any helping words or stories thank you!