Chronic loose stools for months, what should I do? Help?

Hello everybody, I have been having loose stool for several months now. By loose stool I mean a stool that is softer than normal and usually varies from porridge like to almost normal. The frequency of me having a bowel movement has not changed, it is as usual once a day so I am not sure if I can call this diarrhea? I had a calprotectine and PCR stool tests and they both came back normal so my doctor just told me to wait some time more and see if it will get better. I am following this advise but I am not quite sure if it gets better and that worries me. I noticed that I tend to have normal stool when I eat fewer vegetables and fruits and my stool is worse when I eat more of them. So in short, food rich in fiber makes my stool loose or at least this is my assumption. I started noticing anemia like symptoms recently but have not seen any blood in my stool. I also noticed that my brother who lives with me in the same accomodation, has started having similar symptoms which makes me think it might be something contagious but since I have anemia like symptoms, I am not sure what can be contagious and cause anemia like symptoms too? I noticed some improvement though - I started chewing food better and started taking some probiotic supplements over the counter which seems to help me with bloating and also I see no more mucus in my stool which was the case before but as I eating when eating more fiber rich food I get my stool loose. Hopefully, you can give me some advise as even though I am following doctor's advise, its been several months already, like 4-5 months and it is first worrying me but also annoying at this point. Thanks in advance.