It's definitely possible. It happens, but I'm assuming if you were sick enough that you couldn't remember to take your pill, you were probably also not feeling all that up for having sex either. If you did have sex on the days when you missed your pills, yes, it definitely raises the chances. But even still, it's unlikely, even if possible. I think usually they just recommend that you wait a week after your missed pills before you have sex again (or use a condom). I've been on the pill for 17 years, minus roughly a year when I was TTC/pregnant, and I've missed pills plenty of times and I've never had an unexpected pregnancy (even though I got pregnant straightaway when I was actually trying). But I'd just play it safe for a bit until you're sure you're not taking any chances if you don't want to get pregnant now.