Suggest Treatment For Constipation, Gas, Celiac Disease, Headaches And Tiredness

I am 39 yrs old, my weight is 138 lbs. recently I've been dealing with stomach problems, I get constipated and sometimes I have gas... Last year after several test like endoscopy, colonoscopy and finally blood test, I was diagnosed with Celiac. I try to stay on a gluten free diet for the most part... The past four weeks I have been dealing with headaches,, tiredness, no energy and legs aching... Doctors say nothing is wrong with me but I feel like something is wrong. Since yesterday my stomach hurst like in the middle part and after I used the restroom, I had a bowel movement which right after that, I started smelling a fishy smell and after I wiped, I had this yellow mucous looking discharge and it stink.... Any ideas?