Strings in my stool, what could it be?

[chloe123abrams]

I'm 16 years old. Been troubled by digestive problems for a year and a half. I got my gallbladder urgently removed in may 2018 after an unbearable attack and it has gone downhill from there (cause of gallstones was unknown). Constant diarrhea or constipation, troubles me during the night. It hurts about 30 minutes after eating. All my tests have come back negative (a bit of inflammation in my blood though). Ih ave pain around my bellybutton and really bad pains when going to the toilet. I also have been urinating frequently. Recently, I discovered an abundance of longs strings in my stool and I don't even eat anything resembling them. I have pictures. The strings were in my stool for two days and those three days were very painful. Yesterday and today I just had more, after going two weeks without them. What could it be?? I don't think they're worms, they're the length of sheet of paper (pretty long) and didn't seem to move. They only come after I've been constipated. I've also been troubled by extreme fatigue and headaches.  

[CurfewX]

You should have a stool analysis performed.  It could be parasites, but it could also be intestinal lining.