IBS-dD/SIBO

Hi, its been a couple of years i was diagnosed with IBS-D and life hasn’t been the same since. Extreme fatigue. 2-3 loose stools every day. Sometimes floating stool, sometimes undigested food in stools. Have been on all kinds of antibiotics for it and every alternate treatment- homeopathic, ayurvedic etc. Everything seems to work for a while then it stops working. I dont have a lot of pain or cramping. I usually eat fresh home cooked food and try to avoid my intolerances as much as possible. Im unable to digest milk, soy, peanuts, avocado, corn I was researching online and it could be a case of sibo too as i have a white hairy tongue too. Doctors doesn’t pay attention much and say its all in my brain. Have lost muscle mass since last year as i was 73 kg then and im 67kg now Ive seen couple of gastros but they just brush it off with ibs d and a course of antibiotics and say no colonoscopy needed as there is no pain and my ultrasound and fecal calprotien are fine. Is there anyone going through these similar symptoms and can help me with anything that might have helped for them? I came across a post for B1 megadose working wonders for them and im planning to start that vitamin but am just scared if it could cause more harm.

I know life will never be the same now and ive lost all hopes of getting 100 % alright but i just want to feel a little normal again. To just hang out with friends or look forward to getting married and eating a little outside too without worrying what will happen the next day.