You're actually on a head start ahead of too many people if you're at a 4.0 post year 1 of undergrad. Which is a good thing. Moving forward, you can add things to your schedule as you see fit.
When you get doubts/fears in your head, you can
1. rebut them, or
2. acknowledge them to be true, and feel the emotion that comes with it without doing anything. then step back and objectively judge your situation. make adjustments if you think it's appropriate.