About 4 weeks ago I had sex for the first time (protected) it was the day right after my period. I have the most irregular periods ever, I only get it like every three months. Anyway, my friends all say there was no chance that I was fertile and we did use a condom so the chances of me being pregant are very slim. But i've had to pee a lot more lately and i've been gaining weight steadily, which is very unusual for me. With my periods being so irregular would a store bought pregnancy test be accurate, or would I have to go see a doctor for sure? Thoughts, comments, advice all is welcome. Thank you.