Plan b

A condom broke on me and my boyfriend. We have a long distance relationship. We have been dating a year. We was having sex and a condom broke. We got his sister to take us to the local rite aid and we bought plan b and vitamin c. I took the plan b about an hour after it happened. And I heard that vitamin c will help bring on your period. My question is will plan b work if I was ovulating and how can I tell when I ovulated. And any advice will help because I'm only 16.