A2A. I am happy to hear that you have recovered. Being healthy is much more important than JEE or IIT or Stanford or MIT or being owner of facebook, etc.
Coming to your question, I don't think your preparations should be any different from last year. Just get to studying and solving problems. You should have much more time than last year as you don't have to worry about boards, etc. But, don't study for the whole day, keep some time for recreation and other activities. You will be more efficient. Good luck and don't put yourself under too much pressure. If you don't get in, it is not the end of the world. Take it in a stride and move on with your life.
I know it appears at your age that if I don't get into IIT, the world will end. But, trust me, it is not that special. You feel good for a day or two and then everything becomes normal. Don't think that in IITs, life is simple. It is not. Read my answer here:
Indian Institute of Technology, Roorkee: Is it necessary that an IITian will always be happier and above the other non-IITians?