Should I take plan b?

I had protected sex last night, near ovulation. Right after it was over i felt a sticky liquid? On my butt that I thought was his not mine (the texture felt unfamiliar + I've never gotten so wet that it gets on my buttcheek?) so I ran to the bathroom and washed everything off... The outside.. 
Later I found that the condom never came off and when we checked it wasn't broken or had holes in it. Is it possible to have my fluids(?) come out on to my butt? Should I be worried 😭😭 please help