If it is your future that's making you scared, remember this. You have your whole life time ahead of you. You will figure out your career, you'll find somebody to love. You have 24 hours a day.Things will take time but oh well, you have time. Don't you waste it for worrying while you could be living instead.
And if it's people that make you worry, think about this. There will always be people you won't be good enough. There will always be people who want to see you fail because they know they don't have the same cabability to succeed as you do.
So don't worry. Relax. Think but don't overthink. Improve yourself but don't try to be perfect.
"Worrying is stupid. It's like walking around with an umbrella waiting for it to rain."