chondromalacia patella at seventeen and i feel like there’s nothing i can do

i’ve suffered with knee pain my entire life as well as foot pain due to my crazy flat feet. my legs would hurt me so bad in the night i’d just cry and couldn’t sleep. the past year or so it had gotten progressively worse, stiffness and grinding and popping. i got diagnosed with chondromalacia and hyper mobility a couple weeks ago but i have no idea what grade it is because the doctor didn’t do any scans. i have my first physical therapy appointment next week, but i feel kind of hopeless. i’m a waitress and in marching band so i’m always on my feet and sometimes i don’t get to sit down for hours. my legs and right knee is always in so much pain after a shift or practice or football game i drive home in tears. i wake up in the mornings and feel my hips pop and can’t move my leg or knee. i don’t know what i can do