What Causes Irritable Bowel Syndrome, Overactive Bladder And Sexual Dysfunction?

I have symptoms of malabsorption syndrome +irritable bowel syndrome + overactive bladder + sexual dysfunction. My ultrasound of kidneys, bladder and prostate is clear plus my sigmoidoscopy and biopsy is also clear and there are no sign of a disease I had a lot of blood, stool and urine tests done also but nothing was found. I have problems with dairy products also plus I cannot breathe through my nose during sleep. There is mucus in my stool for years now and I have growling noises in my abdomen specially near the rectum area. It feels like there's something like mucus blocking the intestines, I have gas pains and bloating too and there is stunned body growth also. I have a feeling of weight gain one day and weight loss the next day. my sexual desire has also decreased and pelvic floor muscles are absolutely finished I have a sudden urge to urinate and I cannot control my pelvic muscles at all, I have a pain in my testis area sometimes.I have a sudden urge of passing stool its like spasms but its not the stool actually its the mucus I think that is causing this.when I swallow my throat mucus or saliva it also appears in my stool Is there some way I can digest the mucus?I think the mucus causes the noises from the abdomen and blocks the passage causing gas, pain and bloating and everything else and whenever these symptoms happen I feel my skin is dry and weak hair and hair loss plus my muscles are not growing even though I eat a lot but it seems like nothing I eat is becoming a part of my body and all is wasted.My symptoms disappear after emptying my stomach and passing stool but as soon as I eat something after sometime the symptoms start again.please tell me how can I get rid of these symptoms.I have taken medicine for giardiasis,overactive bladder and IBS but no results. my age is 22, height 5.10, weight 61kg.