URGENT: Hiding my Valtrex prescription from my parents

I found out during a phone call today at my job honestly I was too hysterical I had to leave it just didn't make sense I've been sexually active with three people and safe with all of them. I've never even had symptoms for it. I've been tested before and came back clean but I'm not sure if I ever got tested for herpes specifically. My Doctor was not comforting at all and being that I was in the office I didn't have time to ask a lot of questions or react the conversation was a blur but she said something along the lines of

"At some point in time you were exposed to the virus, do you have any idea when that may have been"

I've gotten over the fact that someone I trusted gave me this and I have to live with it for the rest of my life, and I'm not planning on being sexually active/ or dating for a long time 

But my biggest concern is my parents, She prescribed Valtrex to me, saying I didn't necessarily need to take but I took it anyway just because it can lessen the chance of me transmitting it to someone else, or ever having an outbreak but I'm still under my parents medical insurance (I'm 19)

I've been crying myself to sleep out of anxiety because I'm scared they're going to find out. I don't really understand how health insurance works and although I understand I pay a copay the retail price was about $300+ does that show up on a medical bill or something? I know I might sound very ignorant but I'm just scared this isn't like getting birth control, I have genital herpes, there's already a stigma for it and my parents are very in tune with it. They'll be so disappointed in me and they'll start treating me different. I will be judged for it and I just can't deal with them finding out

Is there anyway I can prevent them from it showing up on any statements? I've talked to my best friend about this and she says I'm overreacting but Idk I just want to understand how all this works 

It does show up on the statements but only if you actually do some digging into it.  On my own insurance it shows as “prescription” and then the amount beside it.  If I click on prescription it will show what it is but some companies it just says prescription and you’d have to call to find out.  I imagine because you are 19 they wouldn’t be able to tell your parents.