need urgent help

i moved my betta home from school about 3 months ago and ever since then his tank has been weird. the first thing i noticed was the bacteria growing but i've got that under control. now his fins are clamped and his back fin is completely gone. is levels are fine other than his GH is way high. is it the water is to hard and is causing this, and if so how do i fix it? my parents have been watching over him as i started a job outof town and was waiting to get my own place. i was planning on moving him up here (only an hour drive) on sunday but im desperate for help right now and freaking out. he doesn't have the strength to swim up and stay up anymore hes just at the bottom of his tank. i am so desperate i just bawled my eyes out over these please help i will do anything to save him