Thanks for the report and the great pictures, MikeH! It is pretty likely that your symptoms would have worsened overnight. It's good you got out of there! This was a good first try, and it gave you good feedback -- you will need to prepare more for the altitude next time.
Next time, start out taking Diamox. Try driving up directly to Horseshoe Meadows and spending a night. The more time spent at altitude the better. Also, consider setting up your base camp at Outpost Camp, rather than Trail camp. It would be like another night at HM. You are a fast hiker, so the summit would be easily reached from there.
You really hauled up the trail with your overnight backpack. That energy exertion can add to the AMS symptoms. So a shorter hike, moving a little slower, might be helpful, too.
Is that your tent? Is it cuben fiber?
