@fBoyle-- I don't think it's a good idea to take oregano oil internally. You never know when it might harm your stomach. You probably prevented harm with that glass of milk, smart thinking on your part. But I wouldn't advise you to take oregano internally again, although some people might argue otherwise.
It's much better to use oregano oil topically. It will attack the virus on contact. A safe alternative to taking oregano oil internally, might be making oregano tea from dried oregano. It's safer because it's less potent.