Messy Situation!

Hello! This is my first post so I am kind of an IBS newb. My situation is becoming VERY embarrassing. I am a tournament chess player and lately during intense matches, my stomach begins to hurt like the dickens. I have to excuse myself to the bathroom and then all hell breaks loose. It has gotten so bad that sometimes I spend upward 25 minutes in the stall fighting a small battle against the war in my stomach. When I tell you what comes out of my rear-end looks like thick robust coffee, I'm not kidding These are not your typical bowel movements. These are the 5+ flushers that require a quick call to the fire department to put out the 5 alarm fire that just exploded into the porcelain goddess.
I have not changed my diet at all and never experience D such as this in the past, so why all of a sudden now? I don't know what to do, or why it is happening!!
If anyone has any thoughts or suggestions on how to remedy this curse please help! My chess game has been crushed by the D that has taken over my life.

TIA

Well since my last post yesterday I appear to have been "corked" up like a fine bottle of wine.  Since my post I have yet to pass some D and have been feeling better (I won my last chess match .  However, I can't help but wonder if this is the calm before the storm.  And by storm I mean painting the town brown.  I've had funny feeling in my stomach which makes me think the worse is yet to come.  I do feel better but I don't know if there's enough TP in the world to help with this D.  Any help is greatly appreciated.