missed a pill

so I went to the pharmacy to pick up my prescription today & they told me my insurance wasn't going through, but it's been paid for this month, so I called my insurance company & figured out why it wasn't working, but there was no one actually working today (since its sunday). the only way I'd be able to get my birth control was if I paid $40 for it which I wasn't going to do because I normally get it for free, so I decided to just forget about it & call my insurance company back tomorrow. I'm pissed off now though because I missed a day of my pill & I don't know if it's going to mess anything up. I just started taking it a few months ago so I don't know all that much about it. (I was supposed to start my 3rd month today)