You do not want to just sit in your living room watching TV all day long without doing anything much everyday. That is not healthy. Even though your parents may have been supporting you financially, you still need to do something more productive and actually earn money for yourself. If you have found it difficult to figure out what you can do that can allow you to make money, you actually just need to figure out what you actually enjoy doing. If it is going to gym to work out, then you can become a professional gym instructor.
If you think that this is something that excites you and you want to become a professional gym instructor, then the very first thing that you need to do is to take gym courses. There are a lot of places that offer such courses out there. You just need to work a little bit hard to find them. The first places that you can visit to get the information on the courses are gym centers. Gym centers normally have gym courses or programs for people who want to become professional instructors. You can talk to them to know what programs they have and how much they cost.