Hmm, it could just be one of those IBS thangs... I know that sometimes I can get a bout of cramping C and I have no clue where it comes from!
Anyhow, I would definitely keep up the IF/SF combos: IF to get things moving and SF to give a "cushion". Just keep sipping on warm beverages because dehydration will definitely make your cramping worse! When I get in these situations, I just keep upping my IF and exercise (amount or intensity) until it (ahem) passes. (I also sneak in some regular black tea since I love it and sometimes a gentle dose of caffeine will get things moving.) It isn't a quick fix, but it doesn't swing me over to D, either.
Are you doing the hypno CDs? Do you have a heating pad for your belly? Something interesting to read/watch/listen to? That's how I get over the hump while I'm waiting for the exercise/IF/illicit caffeine to kick in fully....