I know Im new here, but I wouldn't recommend meds to a 16 year old whose going through anxiety attacks...
The first thing you have to do is realize what exactly is going on with your body when having an attack. From the surge of adrenaline your body goes into a "fight or flight" response. Its your bodies way of defending itself when it senses danger. Even if the danger is in your head, your body doesn't know that. Its as if your body thinks someone is attacking you, so its preparing your body for battle. Your body temp might get colder, your eyes may fix more, your saliva could become less, your breathing altered and shallow, etc. So you have to realize, hey, theres a chemical thing going on, so, I need to do something to counter the hyper state thats coming.
The best course of action is to try to exercise if possible. Once the attack starts up, try to get up and get moving. Your body is sensing danger, so exericse to burn off the sudden rush. If you're not in an area where you can move around, (like in a classroom), try deep breathing techniques. I do something called "40 breaths". You deep breath for a count of 5, hold for a second or two, then exhale for a count of 5. Thats 1. Do the full inhale and exhale again..thats 2. Keep going till you hit 40 breaths... It takes about 10 minutes, and usually it will greatly reduce your anxiety. Note: You may have to build up your deep breathing first by doing 10 breaths, then 20, to 40 over the course of a week or two. Otherwise, you could get light headed.
Also, make sure you're getting plenty of sleep. Stick to a routine for going to bed and getting up the same time. Even on the weekends. After a few weeks of getting regular sleep, you may start waking without the use of an alarm, even on weekends.
Eat right. Anxiety can cause nausea, and while its hard to eat when your stomache is in knots, you have to eat to keep your body fueled correctly. That means plenty of fruits, vegetables, whole grains. Avoid caffeine (chocolate, sodas), smoking, processed and sugary foods. The up and down fluctuation of your blood sugar can play havoc on your body, so eat good foods that maintain a level blood sugar amount.
Communicate and talk with family and friends. You need to vent about your problems, and you need a good support system around you that understands what you're going through. Don't be afraid to write down your thoughts in a journal in order to express yourself.
The interesting thing about worrying is that when its all said and done, worrying doesn't do anything, but cause your body to have problems. In the end, life seems to have a way of working out. Sometimes you need to have faith (whether religious or not), that things will work out. You may need to simply tell yourself, "hey, let it go". And realize that worrying isn't going to solve the problem. You need to let things happen, because usually they happen for a reason, even if we don't know what it is at this stage in our life. One of the worst things you can do is start playing the "what if" game... because that can drive you bonkers with worry. So...learn to "let it go"...and keep a positive outlook on your life.
Sorry to have rambled on for so long, but I've read enough, talked enough with different people over the years, and been coaching HS kids long enough to know that there are better methods then meds to get through the struggles in life. However...if you ever, ever feel so depressed that suicide enters your mind...immediately see a professional and get professional help...which could then include meds. ok?
Good luck, and don't worry, things will work out in the end...it always does!