First things first. If you need to talk to someone, message one of the users on Newgrounds. It's anonymous so you don't have to be afraid of it coming back to your home life, I recommend myself, because I are the awesome at listening, and Cally because I know she's cool.
So, my recommendation, is try to eat healthy. Drink some green tea, go for a walk after you've had some green tea and your nice meal. Pet a cat or a dog. Listen to the birds whistle. Scream at the top of your lungs. Break some windows in an abandoned house.
You never really explained where your anxiety is coming from, so all I can say is that there are only so many variables that could possibly cause what ever it is that is making your life miserable. Try to cut out whatever is negatively effecting you the best you can. If you have a tough home life, or you had some really bad experiences when you were younger.
Everyone's had bad or terrible things happen to them, it's about learning to cope. I myself have a dull roar always going on in my head on repeat. I am so use to it, I don't even notice the horrible things it's able to come up with sometimes. I am use to it though and while half the time it's saying "why don't you just jump off the balcony" the other half is saying "I love you".
And remember! Somewhere some kid is trapped in some freaks basement getting molested everyday, so your life can't be too bad.