Super Sarah

Yes, it does sound like IBS. The rash could also be food allergies too. Why not get some tests done for this at the same time or before your colonoscopy?

Also, start taking Metamucil twice daily. This is a water soluble fiber supplement and is safe to take with plenty of water. It will help bulk up your stools and is as good for diarrhea as constipation.

Also, Acidiophilus caps to help rebalance your good gut bacteria. Keep these in the fridge and take them twice daily on an empty stomach. By rebalancing the bacteria, this will help with your diarrhea, any bloating that you may have and also gas and stomach pains.

Calcium supplements are very good for diarrhea and you may find that you are short of this if you have constant diarrhea. It helps the intestine absorb more water back naturally thus helping to bulk up your stools.

Also look at your diet and try some modifications. Ensure that you also drink plenty of fluid.

Try these suggestions and see if they help, but it does sound very much like IBS symptoms to me.

Good luck.