1. You do not have simple myopia you have pathological high myopia (> -6.00 diopters with myopic exudative macular "wet" degeneration.
2. Your injected eye may not recover the vision it had before the wet mac degen developed. You may require more injections in the future, most people do. Without the injections your central vision would likely have been lost.
3. Yes your glasses will look thick even with high index glasses lens but not as thick as regular lens. Yes they make the eye look smaller, all myopic lens do, the stronger they are the more minification. Just the opposite for farsighted (hyperopic) they make eye and world look larger.
4. There is a world wide epidemic of myopia. Much research is going into what can be done to prevent or stop progression. In your type there is nothing that has been shown to help. You can reduce of more wet myopic mac degen by not using any nicotine/cannabis and living a healthy lifestyle. You should not give up near work such as reading and computer and iPhone use.
5. You need to see an opthalmologist every 6-12 months the rest of your life and with any sudden change in your vision immediately. Use an Amsler grid daily. If you don't have one read about, how to test and print one out.
6. Since the macula is 5% of the vision this probably would not make you totally blind but is a threat to your central, reading, driving vision.
7. With glasses that strong contact lens gives better vision as less minification and things look bigger.