Is it possible to "skip" a month of birth control?

I've just been prescribed penecillin (sp?) to clear up a hair follicle infection. But, the pharmacist says that I cannot be on the pill while I'm taking penecillin. I am on my placebo week, and was supposed to start on a new pack of pills tomorrow. Would it be possible to just skip this month and start a new pack in 28 days from tomorrow, on July 8th? Would this affect anything, and would I be protected from the first pill of that pack? Or, even better, would I be able to just skip 2 weeks, as that is how long I will probably be on the penicillin for, possibly even shorter. I'm not sure though, because my periods are extremely regular, and I'm not certain how starting a new pack 2 weeks later than usual would work out. Help me please, I don't have too long to figure this out. Thanks!