I just finished my 3rd sprint Triathlon and was disappointed with my performance, so I'm struggling too. I didn't train quite as hard (my kids took priority this summer!) as my prior tris, which I'm sure is part of it, but was disappointed none the less.

Things I learned, from living with this for a few days:

1) Stuff happens that is not in your control!! For me, it was:
--a cold the week before
--leaky goggles at the start which delayed me significantly
--we didn't use wetsuits, which I thought would be fine, but it was my first time without one in a race (there is a reason why the elite triathletes use them whenever allowed!!)
--the piss warm gatorade they gave us during the run turned my stomach, I couldn't replace electrolytes and BONKED big time on the run--my slowest ever!

2) Things could have been much worse--a flat tire, a crash (heaven forbid), etc. Just going slower than planned isn't the end of the world!

3) Dang, woman! Think of all the couch potatoes out there that NEVER attempted (or would dream to) anything like this! YOU ROCK!

So, feel good about your accomplishments! You finished with a smile on your face. Good luck in your next race!