The antivirals have a history of being safe to take, and won't affect your ability to conceive.
Your doctor is right - you already had those antibodies before you got tested, which means you've had the virus before the encounter.
I recommend you get re-tested, and this time ask for a type-specific test.
Be sure of your diagnosis.
Did you get IgG antibody tests type specific for HSV1 and HSV2, if so what were the results?
Other tests such as IgM are not useful diagnosis tests.
A combined test for HSV1/2 does not infer you have both. Further a blood test can never indicate location, although it is a sound bet for HSV2 to be genital.