OWS and asthma symptoms

I've DNF'd two races in three weeks based on asthma like symptoms during the swim. Let me preface this with the fact that I've got several years of triathlon under my belt, including an ironman, I'm a former high school and college swimmer and have never had a problem with open water.

Two weeks ago I started an Oly swim with a running beach start. I did what would be normal for me-up front, to the side, swim hard for 3-4 minutes to get away from the pack and then settle in. Except that I couldn't settle in, I was hypoxic and it only got worse. My chest tightened, I felt like I could not possibly get enough air and the tingling in my arms got worse and worse. After a few minutes I was actually a bit disoriented and unable to take more than 3 or 4 strokes without gasping and having to breast stroke. I was a concerned and pulled myself out of the race--I'd never felt anything like that.

When I got out, I went and sat in my car immediately, as it as warm, and even 20 minutes later my HR was high, above 75 sitting still in a warm car. For the rest of the day I felt like I had lifted a million pounds-my arms were busted and I just sat on the couch feeling my own blood flow. I took a few days off, and then had a long weekend of one loop of IMLP course, 10 mile run and two swims in MIrror Lake--all totally uneventful, other than I suck at hills and was wiped after hte bike.

Okay, I needed my mojo back, so I hit some open water swims in a different location a few times last week and even bought myself a new wetsuit (crazy!!) and then decided to do a sprint just to prove to myself that the last race was a fluke.

Got there early, racked, feeling confident, did a warm up swim that was fine, to the first bouy and back. THe start was a wade in, I was in front and fully prepared to hammer 600 yards. The first 100 were fine and very hard, then I decided to ease up and keep a comfortable pace, but the same thing happened. My chest felt like there was an elephant sitting on it, my throat started to feel cut off too. I really felt like I was being strangled and had to do back stroke just so I could gasp more air. I finished but was completely wiped out, I just stood there in knee deep water trying to catch my breathe. I walked to transition and seriously considered quitting right then. This time was a bit different in that my lungs were also full of fluid, I could feel it when I was breathing in.

I did the bike course, coughing and wheezing for the first 20 minutes (seriously, other riders must have thought I was going to die). For my effort level my pace was off, my HR was high tempo rate for what is usually an endurance speed. I finished though, and figured I would run okay, I typically run okay even if everything else is bad.

Not this time. I ran for less than 5 minutes. It was clear fast that I could not get enough air to run. Then I quit.

It took over an hour for my lungs to feel normal, and even then I would say that a deep breath feels like crap.

What do you think this is? I swam fine all week in open water, although not that hard pace, just normal pace I guess. I have done two 60 mile rides and two 10 mile runs in the last two weeks that were pretty good, not great, but I leave that to summer heat!

I'm making an appt wiht my dr, but wondered if anyone had experienced anything like this.