You don't happen to drink red-based drinks occasionally, do you? Like Kool-aid? When I have diarrhea and I've been drinking Kool-Aid (or red gartorade, or punch or cranberry juice--anything red, but especially reds from dyes), my stools/water is very red. I almost panicked the first time I noticed this, thinking it was blood, but then I thought, blood is supposed to be dark and this is very bright red. Then I remembered I had drank a pitcher of Kool-Aid the day before. It doesn't really show up any if I have a normal stool because it gets absorbed into the other matter (not to mention stays in there longer).
However, unless you can definitely, without a doubt, link your red stools to something you've eaten or drunk, you should see a doctor and have him give you some test wipes. You wipe with them, then send them off to a lab to see if you do have blood in your stool. If you only seem to get the blood in there sometimes, tell the doctor you want to wait to use them when you see blood. If you have blood, then they should start doing other tests--like stool samples and a colonoscopy--to see if you have IBD.
While gassiness happens with gall bladders, as does bile diarrhea, I don't think I've heard of a gall bladder causing the kind of bloating that you have, nor should you be bleeding. While I could do some smelly poos, I don't recall having a sulphur smell. Of course, you could have multiple things wrong at once, but we'll hope it's just one!