Good work, Tri Girl.
I did a measly 30 minutes on the treadmill, 3 minutes running, 2 minutes walking. I upped my speed on every interval, until the last one was at 6.2. I can't tell you how hard it is for me to run for 3 minutes at any speed. It just never seems to get easier for me, but I keep doing it, albeit, sporadically.