Hello, what is the brand of pill?
When was this?
Was this an 'inactive' tablet, and did you start the new pack yesterday?
As this was the last active tablet, my advice would have been to continue with your next pack starting yesterday. But as we have missed that opportunity then I would suggest the emergency contraception (plan B).
The risk of you getting pregnant is very low, but the gap at the end of active tablets, may slightly increase the chance of ovulation and it is not worth the risk of getting pregnant.