I have been through this dilemma before. Everyone says find your passion, follow your heart and stuff, but what do you do when you don't know where your passion, assuming such a thing exists, lies.
Easy solution, learn as much as possible about all the fields and see if it interests you. Now this leads back to the same dilemma.how to solve this? If you are young, going to a college is the solution.
What if that is not an option? Again a simple solution, take it one day at a time.fixate on a subject and take it easy, dealing with it one day at a time.don't make any future plans, if you have an obsessive nature of planning ahead, try to limit it to next day's plan, nothing more than that.
Move away from a goal oriented methodology to a systems approach; meaning set a few hours each day learning that tech and don't overdo it.keep up this approach for a month and you will notice that you have covered a lot in that subject.If you don't find this subject interesting anymore, then change that subject the next day itself
Keep doing this and you will definitely find certain subject to be of your interest.
Forgive my formatting, typed it from mobile phone