When I was 37 weeks pregnant I woke up in what I considered the worst pain of my life. I remember thinking 'Am I in labor? and if I am I don't EVER want to do this AGAIN!' My husband and step daughter were sleeping. I vomitted ALL of my dinner, the flank pain was unbearable, and I remember just laying in bed in tears. I immediately began drinking bottle after bottle of water and almost immediately realized that I was not in labor but that I had what I like to call "A UTI gone bad". At around 5 am I woke my husband up and told him I was going to the ER. I knew what it was and I knew it was not going away unless I got some antibiotics. As soon as my nurse saw my urine she knew what it was too-- it was so concentrated that it was a brownish/orange color. Sure enough, I had a UTI that had reached my kidneys. The antibiotics were a huge relief by the next night but that kind of pain is something I wouldn't wish upon anyone.
I was in labor with my son one week later and I can't help but feel that this incident had a lot to do with it. Luckily he was healthy and beautiful :)