Hii!
You must be knowing the reason for not studying, it could be procrastination, any distraction or any other reason. But, now that you have realised that you wasted so much time, start studying immediately. Try to complete the subjects you find a little comfortable on. Dont waste time reading now. Buy some sample papers and start solving. This will give you an idea of the exam pattern. Also, you need to work smart to pass in all subjects. Try reading along with solving previous year question papers. Make short notes. Do not be lazy and procrastinate. Dedicate your full time on studies from now.
Hope this helps.
Good luck!