I wish I could help you through this rough time. I think it's really hard for some kids when they go from 2 to 1 nap. My dd did the transition very early (around 13-14 months). It was rough for about 2 weeks (short naps, early wakings), then improved. For quite awhile after that she had early wakings (we always loved the days when she took 2 naps because then she woke up later!)
For your peace of mind, I would at least say it's a phase. Your dd will get back in her groove once she's established a solid 1-midday nap. Honestly, I love the 1 nap much better as it's longer and you only have 1 nap to plan around, so I really encouraged it. Once it's a go, your dd will return to a better nighttime schedule, rising later, etc. I would just try to avoic as many bad habits as possible!