I have had similar experiences.
In 9 weeks of primal, there have been two evenings (a few weeks apart) when I have gone over to the dark side. It's not pizza/starches that get me, though, but rather excessive nut and chocolate consumption.
In both cases I got right back on track the next day with noticeably fantastic workouts (after having only coffee and a piece of fruit), plus I did not want to eat much for the next couple of days.
What a huge mental difference with primal - I have survived these carb craving reloads/refeeds without feeling like I have failed. I simply move on quickly because don't have the cravings anymore and I have had great workouts the next day. Weird but I figure my body just needs the occasional reset. I haven't noticed any loss of energy before these chocolate-fests have hit me.
[The chocolate was around because of other household members, but the problem started with the nuts that I eat regularly, but can get too snacky with. I haven't restocked on nuts lately because of this - they have proven to be my "gateway drug" to chocolate.]