The first and most important thing is to control your breathing , slowly in and out.
Second is to try to relax and rid yourself of the anxiety.

Sit down, close your eyes and look around inside your head. Rationalize with yourself to overcome the false information that is making you anxious. Breathe deeply and evenly until it passes. Teach your subconsious mind that false information is boring you and will eventually be ignored.

I agree. Breathing is the first step to stopping an anxiety attack. Take very deep breaths and focus on your breathing. Closing your eyes will definitely help too.

It also helps to talk to yourself in a calming manner. If you are panicking about a dental appointment, remind yourself that you have visited the dentist many times, and the procedure will be painless and help you in the long run.

It also helps to remind yourself that, by tomorrow, the entire situation will be over. Imagine where you will be tomorrow at this time. Instead of sitting in the dentist's chair, by tomorrow, you may be relaxing at lunch with your mother.

If all else fails, speak with your doctor. Your doctor can prescribe an anti-depressant for every day, which will calm your daily anxiety, and an anti-anxiety medication such as xanax. Tell your doctor each of your symptoms and ask for help!

I actually get tons of anxiety attacks but I've learned to control them using some meditation techniques that I would like to teach to you. I would also recommend doing them before bed, or anytime you need to unwind.

The first technique: The Bubble

Imagine a protective bubble around you. Go into complete details about the bubble, what does it look like? What color? pattern? material? shape? What does it smell like? Would you have any favorite objects in it? Do you hear any sounds or music in it? It's a protective bubble, so anything that could harm you just bounces off or it slows it down so it can't hurt you. Use humor and breathing ot your advantage

The next technique is called 5 - 4 - 3

When feeling anxious or having a panic attack, stop and focus on:
5 things you see
4 things you hear
3 things you can touch
Repeat until you are calm. Breathe and focus on each item


Third technique - Safe Place

Close your eyes and think of a place that you feel safe and happy in. Picture it in your mind. What do you see? Be specific, just like with the bubble. What does it look like? What objects do you see? What colors? What do you hear? Is it day or night? What do you smell? This is best to do in a quiet place if you can, and is very good for getting to sleep at night. Use it with slow, deep breaths

These were just off some notes a psychologist gave me, but if you need anymore, just look up some meditation techniques online. I really hope this helps you!