If you have symptoms of something then tell your parents that. Don't tell them you think you have a certain condition/disease. Explain to them that you just want to go for a check up because you haven't been feeling completely right lately. When you're at your doctors just bring up the symptoms you've been seeing yourself. Honestly, you might just be making it up in your head but you may not. It's best to try to get to a doctor. Even if it's not what you think it may be something else. Even if you don't want to know what it is it would be in your best interest to find out.
You shouldn't worry yourself too much before you even find out though. If you do that when you find out you don't have it you'll just had worked yourself up over nothing. Life is too short to worry about things that you can't change. Good luck.
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She's gone.
She gave me a pen.
I gave her my heart,
she gave me a pen.