That's a great first week V. Good luck with your program.
I'm in the same boat as you on the bike... I can go for a long time but I hate pushing into the red zone. My solution was to try bike racing this year and getting a riding buddy that kicks my butt very consistently and makes me push as hard as I can up hills etc. Ouch. It's a miracle I still like him.
So I wish you well on your speed and interval journey... I literally feel your pain.
Living life like there's no tomorrow.
http://gorgebikefitter.com/
2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS