I'm a senior next year in high school but I don't know what to do! Please help!?

I wasn't thinking about it until now but it just hit me, I realize that next year I'll be a senior in high school, I barely know anything about colleges, careers, or what I want to do in life. I don't know what careers to do because they all seem daunting and I'm afraid I won't do good and mess up, or I'll become bored of that career, I don't know what colleges to go to because there are thousands of colleges, and I don't know what to look for in a college anyways. I really want to know what to do and where to go because I'm completely clueless on what to do after high school is over. I don't even know what to do senior year to prepare for my life after high school.