Tired - need an energy boost!

Without going in depth into your diet/exercise plan - are you getting enough B vitamins?

Could be a matter of what you're eating. My bro and I were just talking about this last weekend. He bought me a blueberry bagel as a treat and after eating it, I felt really bogged down. I rarely eat things like this, and if I do it's before going to the gym so I can burn off some of the carbs and that tends to help with the energy level. Better to get your energy from more long lasting sources like lean proteins and healthy fats and cleaner sources of carbs like fresh fruits and veggies.

I've also heard of people having intolerances to certain foods like dairy that makes them feel bloated and worn out. You could always try to do an elimination diet where you go without the usual suspects (milk, eggs, nuts, wheat/gluten, soy) for 2-4 weeks then slowly introduce these things back in, one at a time, to see how your body reacts.