i'm in high school and all i do is fall down so many times. one time i was just standing up and fall down. my legs are always weak and sometimes and scares me to even get up. im always light headed.
There is a girl on YouTube that had a bout with GBS but also had similar issues to what you are describing. She also had something called Postural Orthostatic Tachycardia Syndrome aka POTS. I think you could be helped by watching her videos. Her name on YouTube is AmazingGrace160. She is currently going to college to become a Dr. and her GBS and POTS happened in highschool I believe.