Yeah, papilladema isn't necessary for IIH diagnosis, but it really seems like something else is going on. There are a lot of conditions that cause IH, so it may just be a symptom of something else.
My pressure drops when I'm upright because my shunt is overdraining, but I feel best when I'm laying down. There are a lot of inconsistencies with your symptoms, so I'm glad you've found someone that's looking into it.
I'm really sorry you're struggling so much..hopefully you'll get some answers soon! We're always here for support..hang in there!!!
Take care,
Julie