Is it possible to have too much yeast?

Just finished a 10 gallon session which I split into two 5 gallon pails.  For the first pail, I didn't realize that the water going into my CFC was going the wrong way.  Then, I stupidly pitched my yeast (rehydrated Safale -05) in 110F wort.  Anyone ever had this happen?  I assume that yeast isn't going to cut it.  Should I just add another pouch of yeast, or would that be too much?

Thanks

You most likely cooked most if not all of the yeast.  The fact that you rehydrated the yeast first may have helped.  To be on the safe side, I would pitch another packet of yeast.

Thank you.  How late would be too late to add that packet?

If the carboy is fermenting, then you have a choice of letting it go or adding more yeast.  If the fermentation seems to be really struggling or lacking, then go ahead and pitch another packet if you have it handy. 

I have added yeast to my fermenter as long as 30 hours after filling the carboy without an issue, but my sanitation seems to be pretty good, and that was with no yeast added for the 30 hours. 

FWIW I hooked my hoses up the wrong way on my CFC on my last batch a few weeks ago. I decided it wasn't worth the hassle or mess of flipping things around so I left it and it chilled just fine... just not as quickly as usual.

Thanks everyone.  The airlock is bubbling pretty good so I think I'll let it ride.