Did you check the fluid level of your transmission:
with car level? with the transmission at operating temperature?
with the dipstick?
If it is indeed over-filled you're going to have to drain it either by removing the drain plug or inserting a hose down the dipstick tube. The danger of an over-filled transmission is that the fluid will foam up causing air to get to the clutch pistons which in turn may cause the clutches to slip and overheat.
I'm hoping you are mistaken and that when you were filling your tranny you spilled some fluid outside the dipstick tube and that got to the floor looking like a leak...
Your dipstick is similar to this. There are cold and hot marks - hot is AFTER driving highway speeds for 15 minutes or more.
CORRECTION: the above is for the 2010 Fortes. 2011 up Fortes have fluid level plugs in which you have to jack up the car and remove the plug when the tranny IS HOT and engine running - best to leave that to a mechanic!