I just finished my period (the 7 days of sugar pills) and was on a combination hormone birth control. I just started nuvaring today. Will I be protected from pregnancy immediately?

Possibly. If you began the NuvaRing on the day you were supposed to start the new pack of birth control pills - you may be protected. If you started the NuvaRing after the time you were supposed to start the new pack of pills you are probably not protected for the first month.