Reading through, I noticed inner ear infections are mentioned. Problems with the inner ear are often dietary, and inflamation/immunity system related. Most common causes being refined sugar, high fructose corn syrup, wheat, and processed foods.
Another concern seems to be loosing some weight, and improve balance.
Fortunately one doesn't need a gym, or a dietician to accomplish those goals.
So, eat like a caveman or cavewoman...no sodas, no fruit juice, no bread, and focus on meat, fish, chicken, eggs, whole dairy, fruits and vegitables.
The simpler and plainer the better. If you want something sweet, try "bee barf", otherwise known as honey on some "natural" peanut butter or plain jane oatmeal.
Eating like that alone will cause a person to drop about two pounds per week.
I'd continue to participate in the physical activities even if they are making you uneasy. Just accept where you're at vs. comparing to others, let the teacher know that you want to do the activities but feel like you need to respect where you are at vs. comparing yourself to others.
Get some physical activity every day. Gym class is probably enough for those days, but pick some activity that you like to stay active with for at least twenty to thirty minutes per day. Start small and build up if you need to.
Muscles in the feet control balance and shoes are the bain of human design. When you are at home go barefoot inside. In the summer go barefoot outside when you can.
Yoga is an excellent activity to help restore balance. There's plenty of information on the web. You might google sunrise salutations for yoga.
Sounds like funds are limited, you might google for body weight exercises. Or turbulence training, or if a park is close by try doing a pull-up or something else.
Even if you only get half of one, then one, then two...just build from where you are.
My friend Eric Moss has a free website that can give you ideas on things that you can do for free to exercise.
The twelve week program he designed to lose the weight is free, there's nothing he charges for at all. Just a valid email address to grant access.
http://rockbodyfitness.com/