You are unintentionally making it worse by using phrases like "helpless". See, anxiety is a function of your sympathetic nervous system. This is important because that part of your brain cannot directly observe the world. It can only interpret the world through your more active thoughts. So when you use phrases like those, that part of your brain thinks its true. Otherwise, why would you be saying them?
Helplessness would release adrenaline because it doesnt know what exactly is wrong, and adrenaline is its all-purpose contingency plan. So at this point, your brain is confused and thinks something is very wrong, because its entire purpose is to save your life from threats.
Fortunately you can also fix it in a similar manner. By not reacting to anxiety feelings, not changing your plans, and reminding yourself that its a temporary bad feeling, you can stop it. Though it won't be easy or fast, it will work.