Missed pills

[zenkatydid.livejournal.com]

So, this is my first month of being on the pill (Yasmin). I haven't gotten into a very good schedule of remembering to take it yet. Here's how it's gone:

Started on the second day of my period, so according to the pack I should be covered after 7 days.
Took the first week and a half's pills on time.
Took a pill more than 12 hours late in the second week - according to the pack this should not risk my coverage, so I should still be covered at this point.
Had unprotected sex with my boyfriend a day or so after this.
Took another week's worth of pills on time.
Yesterday, the Thursday of the 3rd and final week of pills, I forgot to take it, and again had unprotected sex.
Realised I forgot to take the pill today, more than 12 hours late, and took it.

Now. The instructions say that if I miss a pill in the 3rd week, I can either stop taking pills and have a period a few days early, or not take the sugar pills and go straight onto the next pack without a withdrawl bleed.

Considering I had sex last night after missing the pill, and already took the missed pill today, which option should I take? Which would offer me the best protection against pregnancy?

As a side note, it mentions in the pack that if you forget to take a pill in the first week, and you had unprotected sex in the week PRIOR, you could get pregnant. How does that work? Does the pill act as an abortive tool?