Bright red blood in toilet after my bowel movement

I was told by a Dr. years ago that I had IBS.  I will have diarrhea for days and then be constipated for a day or 2.  I have been trying to control my diet more lately...so my bowel movements have been pretty normal.  I recently got really sick with bronchitis and a URI.  I was given an antibiotic and prednisone for 6 days.  When i went to the bathroom a minute ago..I had a normal BM...no pain at all...but when I wiped, there was blood all over the wipe and gone through to my hand.  I wiped again and saw a blood clot on the tissue, when I folded the toilet paper over to see if the clot was bright red or not.  It was full of bright red blood.  then when I stood up...i was speachless!! i have never been this scared.  The whole toilet was full of red water!  What in the world could be wrong with me? Please help me!  Thanks Alot!           Mandi