[Always *]

It's very possible that all the stress you are under is causing your period to be late--it happens, especially if your period is not regulated by the pill. And that in combination with the fear and stress cause by the fact that you are worried you're pregnant could also be a contributing factor to it being late.
However, that being said there is always a risk of protection not working so there is a chance. If you are worried you should just get a pregnancy test. You can buy them at drug stores for usually $10-20, probably closer to the $12-15. You can also get them much cheaper at the dollar store and they're just as effective. Lots of them come in packets of 2 or 3.
If you are pregnant you can seek out your options. If you don't want a baby right now you can go with adoption or abortion.