It’s rare to know what one wants to do. Maybe it would help ease your mind to contemplate that this apparent dilemma is actually one of the great luxuries of our modern age — because choice and freedom, far from being the inevitable state of affairs, is actually a huge cultural accomplishment, a gift to us from previous generations.
At this point in your career, I’d recommend emphasizing two priorities, one a skill, the other an attitude.
The skill is effective studying. A person can be very smart and hard working, yet be unaware of the most effective techniques, and so be stuck in first gear spinning their wheels. It’s odd that schools don’t have courses in this, since it’s the skill that underlies the rest of their mission.
The attitude is hard to name, but I’ll try some possibilities. Quality vs. quantity, or mastery, or everyday genius, or intensity. The idea is that once you commit to something, then hit it with 100% energy and concentration, instead of wasting your precious time. But don’t commit to too many things at once.