Altocelarophobia

This is what I have. I don't even know if this is a real word, since Google only came up with a couple of hits with it. Altocelarophobia is a fear of high ceilings.
I have no problems with outdoor heights. I can stand on the top of the Empire State Building or on the edge of the Grand Canyon with no problems whatsoever, other than standing probably too close to the edge. Take me indoors, though, and the story changes.
My first experience with altocelarophobia (that I can remember) came when we went to St. Louis to see a touring production of the Broadway musical "Annie". I was maybe seven or eight at the time. We were going to our seats high up in the highest balcony, and the far distance to the ceiling combined with the height above the stage freaked me out. I had to leave, and I think I cried a bit. However, eventually I sucked it up and went back in because I wanted to know what happened to that stupid orphan.
The symptoms of altocelarophobia (for me, at least) include anxiety, sweating, and the insane fear that somehow suddenly gravity is going to give way and you're going to be sucked up into all that open space. Then, once you're sucked way up to the top of all that space gravity magically reappears and you fall to your death. Sound irrational? That's why its called a phobia.
For me the phobia is very subjective. Some buildings (like the Gaylord Entertainment Center, or the new Schermerhorn Symphony Hall) don't bother me much at all. Others, though, like the main hall at TPAC, or the Grand Ole Opry House (both of which I prefer to sit underneath the balcony), do not make me very happy.
Still at other times the phobia will come and go for the same building. Take this building, for instance:

This is the Santa Maria Del Fiore, or the Duomo, one of my favorite buildings in the whole wide world. I've been in this building probably two dozen times during my travels to Florence. Most of the time I've been fine standing there in the center of the cathedral, where the height from the floor to the top of the interior of the dome is nearly 300 feet. Last summer, however, when I went to Italy with my friend Brant, I had a near panic attack just walking down the nave of the cathedral, much less under the dome. I had to wait outside while he did the rest of the sightseeing. This summer, things were much better, and I was even able to take the following picture of the dome's interior, although I had to steady myself against a column to do so.

My overall worst experience with the altocelarophobia came at St. Paul's cathedral in London.
There they have a staircase that you can climb to take you to the base of the dome and walk around it on the inside. For some reason I thought this was a good idea so I climbed the 259 steps and came out on the landing at the base of the dome. I was 100 feet above the ground, with the top of the dome another 150 feet above, with nothing but empty, dark, echoing space directly in front of me. My first thought was to just pass out, a bad idea since the railing directly in front of me was barely at waist height. Toppling to my death would have been a bad ending to an otherwise great trip. Sadly, I could not go out the way I came in, and even sadder, the exit was at the opposite side of the dome, which was another 100 feet directly across. Bad, bad times. I pretty much went on my hands and knees and crawled around, looking straight at the floor, to the far side of the dome, ignoring the stares and the whispers of "stupid American."
However, true to the subjective nature of the phobia, I later saw "Phantom of the Opera", sitting in the balcony of a very high-ceilinged theater. No problems there, though I did sleep through much of the second act. That wasn't altocelarophobia, though; it was just boredom.