I have 26-day cycles.

I took plan-b on 08/04/2010, which would be the 13th day of that cycle .

My period arrived 7 days after, on 08/11/10, a week earlier (it would be expected for 08/17/10.

After that, nothing ever arrived. I am still expecting my next period. I have done 2 hpt (although I never catch the first morning pee and the samples used are a little watery)

Is it normal this delay in the second cycle after emergency contraception? Could I be pregnant?

I believe the HCG would be very elevated by now if I were, so the watery samples would make no difference.

The only symptons I have is a PMS that never goes away and a lot of pimples on my back and face. I had a lot of morning sickness the first weeks after the emergency pill, but I believe they were side effects of it.

If I am not pregnant, can I ovulate in this cycle (I'm on the 41th day after the previous menses) or is it a anovulatory one?

Thank you

Sorry wrong dates.

Actually I took plan b on 4th July (07/04/10), I got my period on 11th July (07/11/10) and I am still waiting my next period today, the 20th August (08/20/10)

How soon after the unprotected intercourse did you take the plan b?
It could be your cycle is off because of it, but pregnancy is a possibility.
See what happens in the next couple of weeks and try another test if still no period. It may be you will just skip this month. You could always see your doctor to ask about a blood test.

14 hours after sex.

Most likely it is simply due to the plan b. It can alter the next cycle or two for some women. Odds are your period will return within the next several weeks.
If you don't get one for September as well, or if you are still concerned, check with your doctor.