Welcome-
Is your primary in a bucket?  A lot of time, the lid doesn't seal well and you don't realize that it's going like gangbusters.
Peek inside.  Is there a krausen?  If so, leave it alone.  The CO2 is leaking out and that's ok because there's positive pressure keeping the bugs out.
Is there sign of a krausen ring on the side of the fermenter like this:
 
If it looks like that, it's already fermented.  Let it age for 2 weeks then bottle it.
If it looks like when you first put the wort in, get another packet of yeast and repitch now.
HTH-