Ex-boyfriend's ways is making me feel so unworthy about my next study path.. Like I'm not good enough?

Your ex bf dumped you, you have little connection anymore, and lives on the other side of the world. He has no part of your life, and why would you even give him that kind of power? Move on with your life and leave him in the past. If you lear your mind of him your decisions will become clear to you because he just fogs them up.