Hello and sorry to hear the recent bad news. Yes, you are right that oral and genital herpes are two different things. I have genital herpes and have never had a oral coldsore. You should of course talk to your doc some more but it seems that your mouth is safe.
Herpes is spread when ANY skin comes in contact with an area of outbreaks. It is most commonly spread when there is an outbreak present but can also be spread via 'asymptomatic viral shedding' where the virus is spread without the person having a visible outbreak.
So, yes, someone could get oral herpes from your genital region, but it appears that your mouth is safe.