Anxiety is normal. Don't fight it. Embrace it. Accept it. Think it through, maybe there's a rational resolve that isn't so difficult to arrive at. Some shit just is how it is. Meditate. Stay on the path of whatever you're doing. Mistakes will happen, you'll learn shit and later kick anxiety in the ass.
Think about shit that's not relevant to whatever is stressing me out. Tune the fuck out. Watch some funny shit on the web. Watch a documentary. Jump up jump and get down. Jump around. Jump. Jump. Jump. Jump.