Hi today is August 7th and I just found out I'm pregnant... now I had sex with my ex 2 weeks or maybe less... but I before that I have been having unprotected sex with my boyfriend of 6 months regularly. I honestly don't know who could be the father for sure :S does anyone know who it could be for sure?

That depends on how far along you are .If you assume that you got pregnant mid cycle (usually your most fertile time)which is usually two weeks from the first day of your last period.
You can however,release an egg anytime during your cycle.The 2week mark is the norm but there is no hard and fast rule.
Here is a site that will explain how to calculate the date of conception,
How to Calculate When Pregnancy Occurred | eHow.com (http://www.ehow.com/how_4899369_calculate-pregnancy-occurred.html)