I get this often, too.
Try drinking lots of water and introducing a fiber supplement or eat something fibrous (like brocolli) - not too much, though, too fast. Small amounts at first.
I also "massage" my back and bowel area to try and get things moving. Sometimes that sensation can make you go.
Of course, NOT going too much is a good thing in some instances. Might mean you're going into a bit of remission. I've worried about obstruction, too, with this...when do you know if you're just not inflamed or if it's an obstruction on the way? There are those on this board who have had obstructions and I'm sure they will be along soon to explain to you what they felt like.
Right now, though, try not to worry about it being an obstruction. It very well may not be. I go from having D up to 10 times a day to having these pencil-like stools where I feel like I should be going a lot more based on what I've eaten but then don't. The intestines...such a strange organ when they have CD.
Diagnosed in October, 2004 at age 33.
Current Rx's: Colazal (generic), Nexium (generic), Ferrous Sulfate, One-A-Day multivitamin, Culturelle Probiotic, Omega-3 Fish Oil, Vitamin D, Vitamin A, Calcium-Magnesium-Zinc, Cranberry pills
Secondary conditions: mouth ulcers, joint pain, swelling ankles, extreme fatigue
Previous/occasional Rx's: 20mg Prednisone taper, Flagyl, Levaquin
No surgeries to date