Exposure to HSV

I’m 30 weeks today. I had blood drawn at my 27 week appointment. Today my doctor advised me I guess that I came back positive for hsv, not sure which one though. He asked if I’ve ever had any breakouts which I don’t believe I ever have other than the occasional cold sore that I think I’ve had since I can remember but haven’t had one in a while. After I said no he said well at some point you’ve been exposed to it and that I’ll need to have a shot at 36 weeks of something I can’t remember what it was called.

I just feel so gross now afterwards. I’ve only had 1 other partner besides my boyfriend that I had sex with once or twice. I’ve never even made out with anyone besides my boyfriend so I’m just like where and when was I exposed to it? I don’t want to blame my boyfriend but he very well could have given it to me. It just sucks cus I don’t want to spread it to my child. I’m pretty sure the chances are low of that happening because I’m sure I have had this well before I was pregnant but still. I just hate the thought now that I will forever have herpes in me even if I never have breakouts or any symptoms.

Anyone else experienced this? Am I making a bigger deal about it than I should be?