Help, very scared!!

I have had encounters with someone who I do not know their status. I have never used any needles, but am unsure of the other person. I have been tested for HIV along with all other std's(all negative) They did not test me for hepatitis, how common is it to contract it through sexual contact. I am having many symptoms, such as fatigue, night sweats, join/muscle and pain in my upper stomach. My heartbeat is also very noticeable in my stomach(pounding). I am very worried, I have been having symptoms for about 2 months now. I am going to get tested later this week, what are my chances??!!!!
I have also heard that if you are co infected with HIV and Hepatitis your "window period" can be extended, is this true?

Thanks for the imput