H E L P

Im 19 and my bf is 34, and I havent been using any kind of birth control, and on the morning of 8th of July(it was my 5th fertile day, 33% percent possibility to conceive), it kind of got out of hand, he came inside me, and I didnt use a day after pill.. Its now 11th, I'm starting to get freaked out just now, is it really too late to take the pill? And does it affect my fertility the fact that i'm using antidepressants actively? Pls dont post rude comments
So my q is should I use the plan b now or is it late, or should I wait and see if i miss my period?