Too Tired... Unmotivated... Late night cravings...

I've been very very tired lately. I lost 25 pounds in about 2 months. No extreme dieting or exercising. Just sticking to a 1200 calorie diet and walking on the treadmill for 30 minutes a day and walking my dog at least 3 times a day (15 minute walk minimum). I did a work out DVD every once in a while, but generally stuck to clean eating, and no sugary drinks or treats. I don't know what happened. First, I hit a plateau for a few weeks. I upped my calorie burning from a 200 minimum to a 400 minimum and started losing at a steady pace again (.5 pounds a day). I gradually walked less and eventually ended up eating like crap again. I cook breakfast and lunch most days, but come dinner, I want something quick and I eat bad. On top of that, I wake up in the middle of the night hungry. It's odd because despite my decreased activity, my appetite has increased. I've gained the weight back that I'd lost and have been feeling pretty bad about it lately. But I know I am responsible for my own actions and won't blame these changes on stress or work or whatever. I guess I'm just looking to vent my frustrations and hopefully get some tips on how to get motivated again. I'm doing great as far as eating a healthy breakfast every morning. I do okay on lunches unless I wake up late. Most times, I'll just go the day without eating until I get home. On those days, I'll drink hot tea and hot water throughout the day to curb my hunger. I used to meal prep, but don't seem to have the energy these days. I know exercise is supposed to help you get energy, but even on the days/ weeks that I force myself to break a sweat, I still feel sluggish after the workout.

How can I get my energy up? How can get motivated again? How can I stop these late night cravings? I feel like if I resolve the energy issue, everything else will fall into place.