Could i be pregnant..help please!?

ok so a week and a half about 13 days ago to be exact i had unprotected (yes stupid i know pls refrain from telling me how stupid that was)and for the whole week i havent been feeling to good...ive had lower abdominal pain..sometime its really painfull as if my period was about to come then it would stop...but iv been feelin not to right for the whol week even as i type i feel allit un easy feeling. also todya and sorry for this...when using the bathroom and when i wiped i saw like a red straned i gues blood..but it was just like a strand..within the body fluid .ive also had sever back pains at time ..no tenderness and i have that all the time before my period. ...i alos have stomach pain and feel sick.....could this mean im pregnant or can it be somthign else thats wrong...help pls this is very serious to me..i am going to a doctor this week btu i just want to ask other minds and recieve other opinions. thank you