I don't usually post in this forum, which is ironic because I know the most about OCD than any other disorder (as I used to have severe, severe, OCD). I'm going to try to give you as much advice as I can though...

First off, based on your description, I highly doubt that the test results will come back negative. It sounds like some bad OCD to me. If the test is positive, they will probably go over a plan for how you should treat it- involving therapy and/or medication. If you don't have a therapist or a pdoc, they will refer you.

I don't know how old you are, so I don't know what the reaction will be. But I do know that most parents just want the best for their children and will do whatever it takes. If it helps, ask them to think about it like a broken leg. If you had a broken leg, they would take you to the doctor and get a cast. In this case, the OCD is the broken leg, and the therapy/medication is the cast. It isn't shameful to be in therapy.

If your friends are really your friends, they won't judge you for having OCD. If they do, it's probably because they don't understand really what it is and how life impairing it can be. Just play it safe, and tell the people who you feel comfortable with. If people ask and you don't want to go into detail, simply say something like, the best way to help me is to not ask. There is nothing wrong with saying that, especially if telling them is going to just increase your anxiety. Because the OCD will get worse under stress.

And lastly, CBT. Well cbt is basically doing whatever you don't want to do. Over and over again. So yes, its painful at times. But would you rather have a few times of pain or have OCD for the rest of your life? Because the OCD will only continue to take more and more from you. It will get worse. Doing Cbt at first doesn't feel better. In fact it feels worse. But it gets easier. that's the trust.

PM me any time if you have questions or just want to vent. I'd be glad to help you as best as I can