I’m sure your parents would want you to get help for it rather than judging you for something that’s not under your control. OCD is treatable, and the awful anxiety and fear caused by the obsessions can be managed, but only if you do something about it.
Take it from someone who waited around six or seven years before telling even his parents or even really considering asking for help. I didn’t want to say anything to them or to a medical professional, so I just let things continue, which accomplished nothing except feeding the fear and anxiety further. It doesn’t get better by doing nothing, on the contrary it can have a legitimately major impact on the entirety of a person’s everyday life.
As for what if it isn’t OCD? Well, what if it is? There’s clearly something up, that’s causing you undue stress. I see no harm in getting it checked out. (I do know it’s easier said than done.)