Sounds like the SB flu to me..
A couple things that will help -- Make sure you're getting enough beans and milk (y'all correct me if I'm wrong, but cheese doesn't count as dairy, right? It's considered protein?).. I can't consume dairy or legumes (lucky me, huh?), so I had a glass of unsweetened almond milk, which seemed to help me with the tired, achy feeling last night..
Also, make sure you're doing a "clean" Phase 1 -- no cheating
That'll help things pass quicker as well, because P1 is a detox phase rather than a weight-loss phase, and if you're eating things that are P2 or "off the beach", you're only going to prolong any yucky feelings from detox..
And of course, make sure you're taking your vitamins.. I personally take a daily multivitamin, vitamin B complex, calcium, and vitamin D. Vitamin B is great for energy, and since I don't consume dairy or fortified products, I take the extra calcium and Vitamin D. Be sure to read up on WHEN to take various vitamins as well -- some need to be taken with food, some need to be taken with food that's been cooked in oil, and some need to be taken separately. I know my calcium/Vitamin D has to be taken several hours after my daily multivitamin because it will inhibit iron absorption, which can also lead to that yucky feeling.
Anyway, hang in there and keep to a clean Phase 1, and it'll pass in a short time