Don't feel too bad as worry is just UNCERTAINTY under another name.
I'm assuming you are a teenager of 14-16 or thereabouts and I was one once myself.
Here are two strategies to help you succeed but remember that Math is not every person's strength and as long as you know how to do the four basic operations Addition, Subtraction, multiplication and division and measurement you will probably have enough to get through life ok.
Strategy 1: After each lesson, write down at least three things that you have learnt about. Any new words should be written down clearly with a colon and the meaning afer them, just as you might see a dictionary entry. (Do this within 30 minutes of the lesson and you will really improve your results.)
Strategy 2: Talk to someone about what you have written down. Preferably before that day is over. This helps to consolidate what you know and clear up any misconceptions. (The discussion should be at least 3-5 minutes.
Strategy 3: Visit the internet to Dr Math and ask questions about any procedures you are unsure of. Ther are also other websites that give you answers so you should try them as well.
If I have misjudged your age then I do apologise but by what you have said you bring to mind thousands of other teens out there who have to compete with TV, boys and many other distractions while you are trying to study.
One helpful hint to deal with anxiety is to keep a writing pad (worry pad) and write whatever comes into your head (it's only for your eyes) and after writing for a while about the thoughts that go through your mind you stop and reread it and clear up a lot of confusion in your mind.