Leg pains, nausea, black outs. Come!

I am a 16 year old female. Diagnosed with Joint Hypermobility Syndrome, bilateral pes planus, and accessory navicular in both feet. I injured my right foot in December last year, and a doctor said it was Posterior Tibial Tendonitis. In February this year, I injured my other foot, and the physiotherapist said it was ankle flexor strain due to overuse. I also slightly dislocated my kneecap (according to the physiotherapist) twice last month. Right now, both my ankles and knees hurt. My feet hurt just behind the inside ankle bone (along the posterior tibial tendon / ankle flexors), and on my right it also hurts sometimes on the top of the inside and outside ankle bone. My feet hurt sometimes when I walk and every time I walk down the stairs. My knees hurt on the front, around the patella, and they always feel achy and sometimes hurt when I climb down the stairs. I also recently noticed that I have a funny beating sensation that lasts a few seconds to a minute and it can stop and then come