Often we tend to loose focus in lives. There could be various reasons for it. Most of the things you mentioned here is prob you still need to identify a purpose for life which can provide you with direction in life. You are at the prime age to explore and identify things that matters to you and at the same time this is the age when a person tends to get distracted too. Since you are thinking about it, it is good that you intentionally focus on your life goals. Get in touch with a counsellor who can help you revaluate your life and set goals and action plan for life. Once you are done doing this you can ser the change in the levels of your frustration and sadness.