I finished a seven day treatment on doxycycline for chlamydia and on the day i finished it i had unprotected sex. is there a chance i passed it on?

Yes: Since you did not have the "test of cure" done at the GYN then you can't be 100% sure it was completely cleared.

Chlamydia: If you were very compliant and you finished all your medication as was directed, the chances are good that you did not pass it. It probably would have been a better idea to have been re tested prior to having unprotected sex again.