It's probably not your gall bladder causing a problem. While getting up in the middle of the night is not real common with IBS, there are several people here who are like you--up in the middle of the night, needing to go. Getting up in the middle of the night with a bad gall bladder is pretty common, but I hurt and hurt and hurt before I ever had a bowel movement--at least a half hour or more. And a lot of people with IBS have yellowish stools. The only difference that I can tell between the two is that bile diarrhea--caused by bad gall bladders--becomes progressively more yellow until it's the color of really bright daffodils. And the more you poop of it, the worse it burns. If it's not really bright yellow and you don't really burn, then that's normal diarrhea with just normal amounts of bile in it.
Have you read the posts about taking calcium to stave off diarrhea? Caltrate 600 w/ Vitamin D is the recommended brand. The calcium formula in it has a constipating effect. I have also read that calcium can help soothe and heal irritations of the intestinal lining that can be caused by excess bile, food intolerances, bad bacteria, etc. and I know an irritated lining can cause pain. Last summer I suddenly came down with very painful, daily diarrhea--that's why I got on this site--and I tried the calcium route (at first with yogurt) and I quit hurting and quit having diarrhea. When I stopped the yogurt, the diarrhea came back but thankfully the pain did not. I switched over to calcium supplements and am good to go (along with a medicine I take because I don't have a gall bladder); no more diarrhea or pain. I think I irritated my intestinal lining when I had a bad bout of bile diarrhea following eating too much pizza without taking my gall bladder medicine, and right after that I accidently consumed some sugar alcohol, which I think I'm allergic to because 1 gram lays me up in the bed for two solid days. After those two back-to-back episodes, I couldn't get right again until I took the calcium.
By the way, don't ever consume anything with sugar alcohols in it. These are almost exclusively found in sugar free products and in a lot of low-sugar and no sugar added products as well (ice cream, cookies, Slim Fast Optima snack and meal replacement bars, mints, chewing gum etc.). Sugar alcohols give regular people gas, cramps and diarrhea; for someone with IBS they can be a real killer. And then in some cases a person's IBS is nothing more than an intolerance to sugar alcohols; get rid of them and the person suddenly has no more bowel problems. Sugar alcohols are always broken out under the sugars listing on the nutrition label, or you can find them in the ingredient list--they end in -itol. Common ones are sorbitol, mannitol, and xylitol. And if you consume a lot of sugar substitutes, you might try eliminating them as well. I don't have a problem with any of the calorie-free sugar substitutes, but some people on here are intolerant to one or more of them and they can cause problems similar to yours.
In fact, you might want to try and keep a food journal and write down everything you eat and when and every bowel problem--including pain and gas--that you have and when. This can sometimes help you see a connection between certain foods and problems. A good place to start is to try and make all your food from scratch because preservatives--in addition to fake sugars and fake a lot of other things--sometimes set people off. Then it makes it easier to see if any particular food sets you off. If your Betty Crocker hash browns set you off, was it the potatoes or the preservatives in them that bothered you? If you make has browns from scratch, you'll know that either potatoes are fine for you or they are not fine. It's also a LOT easier to isolate the things that bother you when you make from scratch because processed foods contain little amounts of just about everything. If you have a milk allergy, for instance (not just lactose intolerence), then you are hard-pressed to find packaged goods that don't contain caesin, which is a milk protein that can aggrevate people with a dairy allergy. And people who are intolerant to wheat also have a hard time getting products that don't have a wheat by-product hidden in them somewhere.