YES - you should probably see your doctor again. Seriously, 7 days no sex, or until your meds are all done. Try a condom. This is a serious thing your dealing with here, so why screw around. But yes, you will likely need more meds now. By the way, ask for Zithromax. It is a one dose of 4 pills, and you only take it once, then wait 7 days for sex. Then you wont foget to take it. Make sure you ask for the "One Dose" treatment.
Good luck.
PS - if you don't mind me asking - did you or your girlfriend have symptoms? How did you find out you had it?