Back in highschool, the same thing would happen to me in the middle of football and lacrosse seasons (and sometimes even summer lifting which was pretty intense) and continue on to the end. I would just start being tired all the time, and I would absolutely DREAD going to practices (especially those early in the week practices where you know there'd be sprints at the end). My body just felt like a sack of potatoes. I'd be able to get exited for games, especially in lacrosse season, but I think that was more adrenaline than anything else.
My diet at the time was about the worst thing you could think of. I was living with my dad and he is a vegetarian: we mostly ate huge amounts of cheese, potatoes, bread, and pasta. Those really were what we ate day in, day out(pizza was almost a staple). The fruit and vegetable aspects weren't too good. Later on in high school I started eating alot more meat, and things improved somewhat. But I digress.
If you are eating paleo then you probably aren't doing much wrong diet wise. Maybe try adding more fats (medium chain saturated fats like coconut oil are supposed to be great for giving you energy). But from all the facts you listed, the training intensly for five months really stands out. Everyone needs a break. They say one of the sure-fire ways of seeing that you are overtraining is when you lose your desire to work out. I'd say take 1 or 2 weeks off. You don't have to just sit around, do stuff that is more fun than rounds of deadlifts, 400 m sprints, and pull-ups for time. Play basketball or frisbee with your buddies, go hiking, play your favorite sport. Do stuff that is fun and active but doesn't tax your body greatly. I bet you'd feel better and return to crossfit feeling good.