Anonymous: I recommend you talk to a counsellor, either a psychological professional or a qualified clergyperson, if that's what you prefer. As a doctor, what I take from what you've written is that you are functioning under a lot of pressure, and a lot of controlling, from your parents. You said "they decided I should pursue another degree" and "we're applying for me to do graphic design." Since you are 23, it may be appropriate for you to have more autonomy in your life, and more say in the direction YOU want to take. A counselling professional can help you examine this question, and also help you address those feelings of worthlessness and pointlessness - both of which, along with the other parts of your letter, sound like depression.
You are not worthless, and I think that you just haven't flowered yet. You may need some more time and some freedom to discover your unique value and how you can connect with people, rather than only living out your parents demands and expectations.
I think you've come to the right website, too - EmpowHER - this site is about empowering you as a woman and as an individual. I hope you can find some of that here!
Dr. Daniel Heller