any suggestions for16 year old

i am 16 years old, i start year 12 very soon, throughout my childhood i seen myself as someone with so much energy and mental clarity , now everything the opposite i have severe brain fog and constant fatigue, it started last year, i constantly say to myself it will fade away, its just a groggy feeling, i have tried everything, diet as a kid i always eat clean, i avoid certain foods that have causes sensitivies , plenty of water, good sleep, i used to excerise daily, now walking feels like a nightmare, i just want to study hard and pass my year 12 mark , my dream as a kid to pass the final year with a high atar , i didnt know i would be stopped by this fog , i am super focused that my gut is related to this, i am trying to fix it with bone broth, probiotics, avoiding environmental factors, yet this all make no difference , no gp has giving me a proper answer, only reasoning behind this i can think about is, my mother had a small brain tumor that was removed years ago, i remember she had similar reactions to me , dizzness , brain fog, and memory issues, i dont want to jump to conclusions , maybe i dont know, another possible cause i fear i have mold or dust , we live in a rented home , not the best quality, i always find asbestos signs near the backyard, i talked to my dad he doesnt seem concerned about the effects of mold, myotoxics, or asbestos , as a kid i have no where else to live. any suggestions i would be glad to hear.