You're not crazy in the least. Graduating high school is a scary time, it feels like so many things are ending, to many new things are beginning. It really is very overwhelming. After high school pretty much ALL of your friends will drift away. It's depressing, but it gives you a chance to make new friends which can be a nice new start. I dunno, I'm twenty and still feel lost. I've decided my career path but then I worry, what if I don't want to do this? What if I change my mind. It is scary because it feels like it is to late, I've made my decisions and now I have to stick with them. Being 20 is also very scary :D Just try to enjoy your last year of school. Life will be fun after this, but you'll never (really) have another moment that doesn't have worry, stress, or anxiety sitting quietly in the back of your mind waiting for you to remember your worries. You'll never really be a kid again.
I dunno, I'm twenty and still feel lost. I've decided my career path but then I worry, what if I don't want to do this? What if I change my mind. It is scary because it feels like it is to late, I've made my decisions and now I have to stick with them. Being 20 is also very scary :D
Just try to enjoy your last year of school. Life will be fun after this, but you'll never (really) have another moment that doesn't have worry, stress, or anxiety sitting quietly in the back of your mind waiting for you to remember your worries. You'll never really be a kid again.