Should I be worried?

Jovanna • Jovanna | 22 | With my love since 9.15.2012
I usually take my birth control pill at 9pm when my alarm rings every night; sometimes if I'm out and I don't want to press snooze a million times until I get home, I'll just hope I remember but wind up forgetting most times. On the days that I was a 3.0 & 9.0 in fertility, I missed my pills by accident and took them when I remembered the next afternoon. We don't use any other form of contraception and we don't care to prevent pregnancy enough to spend $60 on plan B... But do you think I could still have a good chance at getting pregnant? What day passed a possible missed period do you suggest testing? I finish my pack on Sunday's and usually start my period on Wednesday or Thursday. 
Thank you!