First of all, it's not too late.

Agar aapne 11th nahi padha h ache se and abhi Roshni Maam k 1 shot dekh rahe ho to, its a very good start. You can understand all the basics and required knowledge about that particular chapter through the 1 shot. After that In school which ever chapter is going on, try to focus on that.. evening time Concepts Add on for JEE are there, so follow them along with your pen and paper, and try to solve all your questions, as well as concepts on weekends. 

You will be able to manage. Whenever you feel, its too much... Take a break of one day in 15 days, and again start withh double enthusiasm.. I am sure you will feel good and more energetic.

always keep in your mind, that this year you have to work so hard and uske baad to bas enjoy karna h.. Try to make small goal and work on that, you will definetely achieve whatever you dream.

All the best!!