Hamley, Since my son lives with us, I know his problems as well as he does, and swear, I suffer along with him. Last September 2007, he had a severe flare,,most of it in lower rectal area. So bad he couldn't even sit or walk!! And he felt a lot of pressure, sorta like he had to go to the bathroom. He wouldn't eat and lost a lot of weight. He got so weak and dehydrated I finally called the ambulance and they took him to the hospital. They did a cat scan and said he had a severe flare in his lower descending colon and rectum. His doctor gave him prednisone, and it cleared up pretty quick. Now, should he feel this feeling just starting, like you do now, he goes straight to the doctor and gets on prednisone BEFORE if gets to that horrible flare like last year. Thankfully, he hasn't had a bad flare since,, not even one in March, where sometime he starts to feel one coming on.
So, it seems for him anyway, if you even suspect you feel your symtoms coming, nip it in the bud, and get on the Rectal meds right away.