No worries mate.

I definately dont think she is pregnant, my husband and i used the only pill for years, and as i said i was a bit lax on that occassionally and in 5 years we only got preg when we wanted to

It does sound a bit weird with what has being going on previously though in her cycles, it could be maybe she might need to be on a stronger pill or that maybe even her natural cycle is trying to kick in!! I have heard of that happening!!

Maybe if she is really worried she could go see her GP and just let them know and he may describe a new pill for her.

Good luck, i hope i am a bit of help, but im no Dr!! LOL like i said, if she is really worried, go see a doc!!