Welcome to the board!
Urgency is quite common for IBS, but accidents while sleeping are not. You really should see if you can get in to see a GI (or your doc) as soon as possible.
Your doc will probably be able to prescribe an antispasmodic which should help with the pain and urgency, which might also help with the accidents.
Have you tried taking any OTC meds for the gas? Something like Gas-X or Beano? They both work pretty well for me. Fennel or mint tea also do great for me when I have cramps and gas.