My body let me down... sort of

My tri from Saturday was a beach start.  I have done it hundreds of times on my own and growing up... Im at home in the water and the "washing machine" does not bother me...

So it was COLD before the race.  I was wet and shivering, could not get loose... then when we started I dove in, the first breath I took and I inhaled some water... I have had this happen before and I just stick to my rhythm and take a big breath next time... only this time... my whole throat closed up... I could not cough, inhale, exhale... nothing. I did not panic, but I could not put my face in the water.  I kept moving forward- 10 yards form shore and Im side stroking... about a minute later my throat relaxed, I took a big breath, and set a new PR for the swim...

I would have beat the majority of my AG but not for the "incident".  Looking back, my run was so slow, it would not have made much difference anyway, but I was pumped for the swim...

THEN, because I was so cold, my legs felt like they were dead the rest of the race. 

Im buying a wetsuit the next time the $99 deal comes around for sure.  

ANyway, anyone ever have this happen?  How do you get past it?  I know its just my body reacting to prevent me from drowning, but CUMMON- Im Tri-ing here!