My fertile days are between Sunday, Jul-12-2015 and Friday, Jul-17-2015 I started ovulating on Wednesday I had sex that night what are the changes?

Definitely possible. Unprotected intercourse in the middle of your most fertile time certainly gives you a good chance of pregnancy if all else is normal. If your period is late or abnormal, do a pregnancy test and repeat it in 3-5 days. Overall, fecundity (the chance of getting pregnant in any given cycle) is 20-25% for women under the age of 30 and slowly declines there after.