Should we be worried?

My girlfriend and I recently had unprotected sex. She had just started the pill, and had been on it for about 5 days. I found out afterwards she had been late in getting her period, but the last time we had had sex was right after her last  period and we used a condom, without problems. We're unsure as to whether or not to be worried, and what steps can be taken to get some peace of mind.

[remar]

So she did get a regular period, or was it very light?
Did'nt her Dr tell her to use protection the first month of being on the pill? Use something until her next cycle.
Since you used a condom with no problems it's unlikely she's pregnant but she may want to take a test or see her Dr. She should not be taking the pill if she's pregnant. Take care. Remar