I've never had even a remote fear of heights. Starting last year that started changing slowly. At first it made me uncomfortable being around someone near a ledge in a high space even if I wasn't near the edge. Now I'm really affected with the most irrational anxiety around heights.
Was at a hotel a couple weeks ago, only about 15 stories, but it's one of those rectangle buildings with an open inside atrium like space. Was on the 14th floor, got off the elevator, looked over the edge as I walked to my suite and "NOPE". Let's just say I walked briskly along without another peep over the edge.
Weird.