Anxiety Support Group
Anxiety is a physical condition marked by intense and persistent feelings of distress, fear, angst or dread. General anxiety caused by routine day-to-day stresses usually passes quickly and is experienced by almost everyone at one time or another. However, such feelings that linger over time and are very difficult to cope with, and which lack a clear cause, may indicate...

There's nothing wrong with your feelings and your worries - they are natural.
Try to stay in today. I've noticed that high schools are telling a lot of young people that they must go to a really good college or whatnot. The truth is that in order to get a job - you don't need a really great school. What you do with your education is what's important.
And if you don't get a scholarship, there are always loans. Nobody wants to be in debt, for sure, but when there's no other alternative, what can you do?
One thing that helps me all the time is to remember - feelings aren't facts. Fears aren't facts. And these change every five seconds. I've got to stay in today - and put off tomorrow until tomorrow gets here. I can't handle things otherwise.
If you're this worried about succeeding, then it's likely you will succeed, because you CARE.
That's where you figure out when you study for this, and when to study for that. And what you have to do by when. You have to make a timeline somewhere or somehow (ask a teacher or a parent) to plot in when all your assignments and tests are due. Then you just work to the next one.
You blot out everything you can't do right now, and focus on what you can do.
Keep up with your reading and homework, set up times that you will do this.
Surviving the panic is all about chugging along, getting the time in, doing the reading, not getting behind on homework.
When you get behind the anxiety goes through the roof. You can get so anxious you get paralysed by it and don't know where to start. Start at the beginning. Do your homework properly, and if you get behind go tell mum or dad that you are behind and need help structuring your time. Or if you're having trouble with motivation to get up and study - tell them. Let them help you. Grownups have to learn this, and you will learn it during your school years. They will walk on hot coals to help you. But you will have to do the actual work!
I have a timeline in my head that I work to, and which drives people around me up the wall if they don't know what is going on. Like at work: we had to move today. For the last week I have been preparing, but I have not been 'seeming' to prepare. I've archived 60 boxes. I've cleaned up my files. I've done all my urgent work. I packed everything on the last day. My boss wanted me to pack three days ago and has been bouncing up and down about it - but if I do that I can't do any work. I didn't obey his panic. I did what made sense.
Some panic and want everything done now, harem scarem, and can make a huge mess. Lots of time is wasted undoing things, and doing them again, and jumping from one to the other. I refuse to panic, I set up my own timetable that makes sense to me and means I always work to the next deadline - and then I chug along. Others think I'm slow but I am FAR faster than them, and a lot more efficient.
So go figure out your deadlines, make sure they're all written down and you can't forget them, or miss them, and then figure out when you are going to study what, catch up on which, and then just work to the plan and you will be absolutely fine.