Take a HPT test. Or see a doctor for bloodwork. the bloodwork checks for the pregnancy hormone and it will let you know exactly where you are at in your pregnancy... if you are pregnant.
You may finally be getting your period. If you had sex on the 9th I would wait till OCt. 9th to test.
You could very possibly be pregnant. I would say take a hpt. If it comes up negative then wait a couple of weeks and test again. If it stil comes up negative and you truly feel that you are pregnant, then make an appt for a blood test. Good luck