I'm on Mavelon (this happened as well on other bc's). There is once in a while when I'll skip a period. I used to run to the pharmacy and pick up a home pregnancy test, but I never ended up being pregnant. I recommend getting a pregnancy test. I'll bet it's probably negative. There are tests that are good to take 1 week before expected periods... ask a pharmacist, they're wonderful.
I usually had an extra heavier period the next month... My guess is that it's just a false alarm... Weight loss can cause funky periods...
Things to look out for while on Birth Control pills:
Grapefruit - for some reason it can lower the effects of BC pills (learned this from my pharmacist!)
Antibiotics - This is very risky for lowering the effects... I recommend using another form of BC while on it
Blue cheese - YES... PENACILLIN!! Blue cheese is blue because of the mold. It's not a big risk, but it's still there.
Never forget that the pill is also only 98% effective. If you have any worries, the pill and condoms combined are always a good solution. There are some AWESOME products on the shelf that can heighten the pleasure for both youself AND your partner
If you can't find anything other than plain old condoms at the pharmacy... go to a sex shop (For some reason, I'm more comfortable buying them at an adult store than a pharmacy... to each her own I guess)
Hope it works out for you
And Merry Christmas, hope you have a wonderful vacation!!!
p.s. I'm notorious for forgetting a pill here and there. Of course I don't recommend skipping pills, but I haven't had any problems... yet LOL
P.s.s. For me (everyone differs) my first sign of pregnancy *I have 2 kids* was the morning sickness (not everyone throws up, but the nautia is there), tiredness and horrible cramps. Cravings didn't really start until my 2nd trimester