Diagnosis coming up... scared I won't get one?

I'm on a waiting list to get a potential diagnosis for my suspected contamination OCD, and I'll likely get a call in 2 or 3 months. But I'm scared that they'll tell me I don't have it, and for some reason that really bothers me because it feels like it is such a big thing in my life.

Anyone who got diagnosed (college age, if that matters), what was that like for you? What do I do if they tell me it's not OCD? I feel like it would be so much easier to explain what's going on with me and my brain if I can label it as OCD, use terminology etc. instead of the personal terms I've made up and have been using for the past 4+ years.

And thoughts, experiences or follow up questions appreciated. Thanks!