Need Help ASAP! O/D Off light Flickering!

I was just driving my car home today and the O/D OFF light started to flicker. I don't know what this means? The car isn't shifting very smoothly anymore. I'm gonna check the transmission fluid as soon as the car cools down? Have you guys ever had anything like this before? If so, what was it?

Well I just checked the tranny fluid and it's fine, and red. However, my friends dad who's a Chevy mechanic (for 20 years), and who installed my prochamber, noticed when he got under there that I did have a tranny leak. He said it was the extended housing seal? I don't know if that would have anything to do with it though.