The serious symptom of your prescription is caused by the bad habit of using your eyes. You must make the eyes feel tired and then the eye muscles will be affected. Then your eyes get higher prescription. You should protect your eyes carefully. You'd better have the regular time for your eyes to get rest. Eating more food with vitamin A and C is also good for your vision.
Well, as a matter of fact, I quite understand your anxiety over your myopia. So, as you can see, the decrease in our vision is a slow process, it just decreases gradually at a steady pace. So, if you do not take care of your eyes and eye health, you are likely to have a bad vision year after year. However, if you pay due attention and take some measures, you can reverse the situation. Hope you stop worsening your vision.
Well, in some degree, your prescription can change before you are 20 old. As we know that myopia prescription can stop after reaching maturity by age 20. And you also need know that the layers of eyeball coating are relatively fragile compared with adult eye, and the eye at this young age is still developing. So if you are wearing glasses for a long time, it can cause rapid vision deterioration that is then followed by eyeball elongation. Also, there are many factors which can influence your vision such as hormones, chemo treatments, and fluctuations in blood sugar. It is constantly changing in one way or another, which is apparent by your prescriptions. Anyway just be careful about it.