extremely bad stomach problems! :'( help?

im 20 years old, and have had IBS since i was 14. ive had both my gallbladder and apendix removed because of it, and it still continues to get worse. its been a couple years since ive been tested, but ive had a LOT of tests to see what is wrong, and they all come back negative.

i go to the bathroom, on average, at least 5-6 times a day. some days ill go 15 times. it all depends on how my stomach is acting. VERY rarely will my stool be solid; its ALWAYS diarrhea. lately ive began noticing a yellow substance that almost looks like transparent skin. could this be my stomach/intestine lining!?

also, my stool is a dark brown, almost blackish, and is stringy. also, there are reddish chunks, that also make me think it could be parts of my stomach, or whatnot.

please, if anyone could give me advice on what they think it could be, please respond, or email me at savestheeday@gmail.com. im scared to think that this could be something very serious!

thnx!