Hey, i'm 18 years old- so I know how doctors can be. Any problem you explain, it's because your 'stressed' or a smoker, or hell, even that you're fat.
They simply assume you're incapable of knowing that something is wrong.
I personally changed doctors 2 years ago, to a better practise and my doctor has more time for me and patience. Even if you're fit and healthy, your doctor should have picked up on your 'anxiety and hypochondria'.
I personally live with various forms of anxiety and OCD. I always have the feeling something is wrong and sometimes it affects my study and can get me really down. I can't eat anything anyone has touched. It's all about having control of my own life, which a lot of teens struggle with because of controlling parents.
Chances are, when you were younger, your parents or guardians over reacted when you were ill, or put you in an awkward situation. So I look at anxiety and hypochondria as a state of habit, rather than an illness.
The next time you're ill, or think you are, ignore it.....don't go to the doctors. Pretends it's fine. If nothing happens, you will realise your body can control your illness and you don't need to rely on a doctor. If something bad happens, no doubt you will go to hospital, where they will look after you properly. It's a win win situation.
As for Anxiety, counselling will not help, trust me, I've had 6 years of it. You have to learn to accept it, or prove to yourself you're been silly, make it a funny subject.
Know that YOU ARE in control of your life, everyone else is irrelevant.
Only ever rely on yourself, because nobody knows how YOU react to YOUR anxiety, only you. To doctors, your just 'another' patient. I'm currently making everyone touch my food. It hasn't harmed me and I am therefore learning that being a germaphobe isn't improving my way of life, and am slowly recovering.
Instead of asking yourself what anxiety and hypochondria are doing to you, ask yourself what they are not doing to you- because they're not benefitting you, they're not helping you and they're not improving you, are they?. Because if they were, you wouldn't be on here.
Remember, you're in control.