I Just Started Taking Doxycycline Yesterday... I Do Drink Coke

I just started taking doxycycline yesterday... I do drink coke zero and took my first three dosages while drinking the beverage. Did I happen to decrease the effectiveness if it by drinking it with soda? Also can I have soda while on the medication? And at what point after taking the medicine is it okay to drink the soda? Thanks so much for your help...