condom slid off as he pulled out, on birth control but should I take Plan B?

Hi,
Had sex Sunday night with my boyfriend and for the first time, the condom slid off as he pulled out to switch positions. I had to go deep in me and pull the condom out. He said he did not ejaculate yet. I am on the pill and take it daily but not at the same time everyday but I take them. 
Should I take a Plan B just in case today? Or would my birth control be enough? 
I don't want to take a Plan B if I don't need to but it's only been 2days since sex. Help :(
ALSO, has that happened to anyone else? Condom sliding off inside you? What did you do? Is there anything I should worry about?