"Cold" water swim yesterday... need advice

I want to be able to do some cold water swims w/out a wetsuit, but now I'm not so sure I'm capable of such things. In fact, yesterday, I was pretty sure I'd never try a cold water swim again. And it wasn't even that cold by the standards of some of you. Air temp in the 40s, water temp (I'm told) 56... although I also heard low 60s. I'm not yet a good judge of temperature so I don't know. Weather got a bit chilly the last few days, and yet I'd planned to join my masters' group for an open water swim and I wasn't about to pull the plug on that without a fight. ;) I also had thought I'd be strong, not wear a wetsuit. (I don't even own one.) But at the last minute, I emailed a friend and asked if I could borrow hers--she was going to watch but not swim. It occurred to me that given my lack of experience swimming in those conditions, I should start gently, not go right to a swimsuit. But I still felt like a wuss. We swam laps around a buoy placed (I think) about 100-150 yards away from the dock where we went in. My thought was to go four laps (I know, pretty short) and see how I felt. First lap my chest felt very tight and I had a hard time breathing. (That might have been the effect of the wetsuit--I don't wear them normally and managed to swim okay without one a few days earlier--water in low 60s but air temp wasn't as cold.) Then I began to feel more comfortable, swim more relaxed. But I still didn't quite feel as if I was adjusting. On the last lap, I was going off course and hit my head on the dock--luckily at my speed it wasn't too hard a hit, so I wasn't hurt. But I decided that was my stopping point. It took me a while to stop shivering, but that wasn't unexpected. What concerned me was how long it took to recover--the rest of the day I felt under the weather, sore, exhausted, even with such a small amount of swimming. Don't know if this had anything to do with it, but before the swim, I thought it might help if I took a run--overdressed so I'd be warm enough to want to jump in (maybe a mistake). So I ran about a half hour w/ a backpack (probably about 4-5 lb not heavy), and yes, I was pretty warm but the dressing room was chilly, and getting the wetsuit on took a bit of time since I'm not used to wearing one. I'm wondering if the soreness had more to do w/ the running or with the fact that my muscles tightened more than usual in the water or what. Now I'm rethinking whether I should even consider anything in cold water, such as Boston Light which has been my goal--but 8 miles in what felt like a struggle in a wetsuit for such a short time? I'm not so sure now. I know it's not until next year. Also my longest swim this past year was seven miles (albeit a very slow seven miles) and I was able to PR in a 5.5 mile swim in July (current assisted, but still...) at a pace that would allow me to finish BLS (although overall, I'm not a fast swimmer, so maybe this would be too much race for me now... or at all). I love trying new challenges, doing what i'm afraid to do--well, maybe "love" wouldn't be the word I'm thinking of, maybe NEED--and despite how I felt yesterday, I don't really regret the swim, more the fact that I was so wimpy that I was the first one out of the water and that I wore a wetsuit. A friend was in for an hour without a wetsuit! And she loved it! I admire her immensely! But could that ever be me? I don't know. So those of you who now regularly swim in cold water--did you enjoy it at first or was your experience similar to mine? Or... is there hope that I could get to like this? I didn't like spinach when I was a kid and like it now, so there's that... and I didn't like running uphill until I heeded the advice of Olympic runner Jeff Galloway during a running clinic to repeat to myself "I love hills"--and lo and behold one day I was running up a hill and thinking how much I enjoyed it... and thought, "Jeff, you rascal!" ;) What tips do you have for before, during, and after (besides losing the wetsuit, which I know I'll need to do... i saw the wetsuit as a kind of stepping stone). Thanks for any advice/feedback. I still want to do BLS. Now I know I'm a sick chick! ;) (And I have to admit when the rower I talked to briefly when I came out said I was crazy, I took it as a compliment--but felt I hadn't really earned it.)