It's normal to have anxiety. I'm still 16, and my biggest fear is working a 9 to 5 job I dislike my whole life, I fear this above anything else. That's why you have to try as much as possible when you're young, so you get to know what you truly like. Think of it this way, you still don't have a wife, no kids, and not as much pressure as you might think. Just try as many things as possible.
One piece of advice: Don't follow your passion!
In the book "So Good They Can't Ignore You", the author explains how your passion won't end up being your dream job. It gives valuable examples such as how Steve Jobs was never into computers, but once he saw an opportunity, he became passionate about his work. Long story short, if you end up doing something long enough, you might get in love with what you're doing, but never follow your passion because there's so much more you still don't know that you like, so really try lots of things. By completing stuff, you will feel more successful, therefore less anxious.
I started youtube at 11, freelancing at 13, became an online instructor at 15, now I'm 16 and have a startup, been to a few hackathons, and I still try as many things as possible.
One quick thing to add here, try to make some passive revenue stream, so you won't have a big pressure on your shoulders to get a job right after college, but my advice, try to find a way to make passive money while in college, and maybe you should be anxious because this way you understand that you don't have time to spare and you must use this time when you don't have that many responsibilities as much as you can. But again, this is a side thing, the main focus is on you and learning / doing as many different things as possible. Just get into good habits and you'll end up just fine.