Based on what you described, I would say enjoy your time with your grandparents, engage with them, make them speak about their life, learn their life history if you can. Try to find a job, any job, even if it's a braidead job, it will give you objectives, it will make you interact and meet people, if you can't try to do some voluntary work, for the same reasons. Do some exercise if you aren't already doing. Try to learn or read about subjects you like, or learn a new skill, today we have tools to learn almost anything, you can also volunteer to job job to learn something. The main point to me is, help people, get something to do, paid or not, learn, meet and interact with people, don't close yourself from the world, interact, keep an uplift spirit, and things will flow, don't think too much about purpose, enjoy people and life with an open spirit is my advice.