IBS?????

I've had spastic colon for years.  I am 56 with good health.  For the past several months, things have been different.  I had a bout of 3 days of passing nothing but bloody mucous.  It stopped.  Has a similar incident that lasted only 1 morning several weeks later.  For the past 5 weeks, it has returned and has gotten worse.  No diarrhea, just bloody mucous with blood in stools that are small.  Not every time, but now every day.  I can't leave the house, unless I take some lomotil and that only lasts a little while.  I'm not eating much as food worsens it.  Sometimes, I can't even make it to the bathroom and I'm only in the next room.  Sometimes, I have no warning at all.

My back and legs ache just prior to bm, my stomach is sore and crampy. Sometimes just walking around causes an incident.  

I've had a colonoscopy and the dr said I was perfect.  If I'm so perfect, why am I having such trouble?
thanks for your help