Talk to Eye Specialist on Weak Eyesight

I am 24 and have been wearing glasses since 8 years. Mu eyesight number started from -1.5 for both the eyes. Now i have checked my eyesight yesterday and its -6.5 for both eyes. I am worried why my eyesight kept on decreasing on every check-up. I want to go for lasik but the doctor said you cannot have laser until and unless your eyesight has stopped changing and you have a stable eyesight number for two years. Kindly advise me why is my eyesight getting weakend day by day. Suggest me any multi vitamin , eyedrops or supplements to stop the eyesight from decreasing