The guy who was responding to you doesn't believe in repressed memories; it's as simple as that. You either believe that what happened to you, happened, or it didn't. I don't think there's really a conversation for you and that person to have, because you remember your memories. Plain and simple.
The valid point on that thread, made by someone else, is that you may have been experiencing psychosis. If that's true, then your memories are of your psychosis, which could have been influenced by real events, but may not be accurate to real events. This is why drug-induced psychosis is excluded as a possible cause of PTSD.
And the other valid point is that (at the end of the day) it's for you to work out with your doctors.