For a little over a year I have been getting dizzy spells where I can't stand up without immediately collapsing and I don't know what to do. It started one day as far as I can remember when I got "stuck" standing because I couldn't bend my knees without falling. I usually get dizzy when standing for a long time or after standing up from sitting. My heart rate is usually over 115 bpm when I feel this way. It is also higher when I stand up then when I exercise. What should I do.
I also have one teacher who thinks I'm and I quote concerningly hyper mobile. My knees go far past 180 degrees as well as my elbows and every joint in my hands is hyper mobile and my ankles. Recently my joints have bent cauing me a lot of pain. I don't know if these are related though.
Obligatory not a doctor, purely arm chair diagnosing, but have you looked into Ehlers-Danlos Syndrome? Sounds remarkably close to all the symptoms you're having. Also possibly a related diagnosis of POTS?