Tired of being tired

I've always been a crappy eater. My tastes have expanded over time, but mostly just to include more crappiness. When I was younger I ate whatever I wanted. My senior year of high school I ate a 3 pack of hostess cupcakes every day for snack, and I weighed 112 lbs. All that sugar equaled a whole lot of energy.
Now I'm just plain tired so much of the time. I know that I'm not 17 anymore, but I'm not that old either. My lifestyle is a little different. Working full time, taking care of 3 kids and a home is a little different than going to high school and working part time, but I also know part of it is my diet.
I've been curbing my eating in the past 6 months in an effort to lose the rest of my Caliana baby weight, and it's worked, but it's not like I'm steaming veggies at work and stocking up on high vitamin munchies.
Price and convenience are huge variables here, because I'm kinda cheap and a lot lazy. So why is that a salad costs me six bucks and a taco bell burrito is 89 cents? It's unfair I tell you. I have only coffee for breakfast and drink a whole lot of diet dr pepper (aspertame anyone?) and will pass up milk for an energy drink because a glass of milk eats up 3 of my weight watcher points, and that sugar free red bull is 0.
All that up and down and not many vitamins is leaving me crashing and burning more days than not. But I've lost the weight. I must be doing something right I guess. Ok, not really I know. Eating right is hard, and honestly I miss the cupcakes.