The first is diet. I am trying to lose weight in stomach area while build muscle elsewhere which I know is tricky. And ill admit diet is horrific when it comes to when and how much I eat. I eat 1 "big" meal a day, which is either lean burgers on wheat buns or a chicken tender sub from the local supermarket. Then I have protein shake after workouts. And on most days that is all. Hahaha I know thats really bad. I just don't know how to cook and I have been doing okay for 2 months on that type of diet, losing stomach fat AND gaining a little muscle. I know a lack of carbs can cause fatigue, but it seems weird that this diet is all of a sudden unacceptable for workout program. Sure I need to eat better, but why would it be downright draining me now when it worked for so long?
The other, less likely, is maybe overtraining. I have read the "symptoms" of overtraining and they are spot on for what I feel, but it would seem that overtraining syndrome would come more gradually and I would also feel it in muscles, which feel okay just a bit weak and fatigued. The only reason I am considering it is because I am getting 8 hours of sleep a night, using a diet that was working for 2 months, and yet I am tired and shaky during the day all of a sudden, as I said before

Just a PS: I have a history of depression and anxiety, and still deal with the anxiety disorder but I am doing much better. I mention it because stuff like this is what anxiety feeds on, feeling a certain way that I think I shouldn't feel. The hypochondria and anxiety in me are obsessed with thyroid problems or maybe depression returning as the source of these issues, but I am trying to stay in the mindset that the simpler answers are more likely. So I ask, could poor diet habits even though I don't overeat be the culprit of these fatigue problems? Could it be overtraining since 2 months ago I didn't work out at all. Combo of both? Today was the first day I have cut a workout short for any reason, and the fact that I cut it so short because I simply felt sooooooooo drained worries me. Any ideas friends? Trust me I won't be offended if you respond with "it's your shitty eating habit you idiot" lol.