Yes, I have decided and have come to learn that I am on this earth for a reason and that I do have a purpose. You can feel the same way too. The trick is that you have to find a purpose in life that interests YOU! This is the only way you will be any good to yourself and/or to the world at large. Then you follow it like gangbusters!
If you find yourself at the mercy of everyone else's wishes then you have some major recovery to do. If you listen really close, maybe even plug your ears, you might hear or feel something that feels like YOU. At first, you might not recognize your own voice but you need to learn to trust yourself and ACT from that place. You might feel scared when other people go against you for standing up for yourself. You will probably hate the feeling that others are disapproving of you. This might SEEM more painful than "sucking it up" (doing the other guy's wishes) -- just one last time -- but it's not. Don't fall back into the trap unless you want to see the complete death of YOU.
The one thing I can advise, to start, is this: Say what you think, DO the activities YOU are interested in (and not things you think you SHOULD do or other people say you SHOULD do) and see what happens. In the beginning, try not to step on too many toes, unless you are accustomed to doing this. SENIOR to everything, is keeping a pure heart. Make sure your actions are leading towards a survival and ethical goal (example - starting a good business, pursuing the arts, volunteering for a good cause, etc. ad infinitum). If your goals are perverted or unethical you won't get far and you will get really sick or someone else is gonna stop you. But REMEMBER, whatever you choose to DO, make sure it is an activity of you own choice and NOT somebody else's.
As you do this, you will start to see yourself evolve as a person and people will be drawn to you and interested in you.
FOLLOW your INTEREST!!!