You should be fine but i would take a Plan B just in case. I would always just keep some condoms around even while on birth control just to be safe. (pull out doesn't matter, I got pregnant just from one time and he pulled out)
So, you missed one day, took it the next day then were just late by a bit the next couple days?
Or you missed three days straight and then took the three missed pills?
Especially if it's the latter, I would get Plan B. Be aware it is a huge dose of hormones and therefore can cause you to start bleeding then, spotting, or even delay your period.
The first situation, I'd say you'd probably be fine.