Sleep is a big deal. I find if I'm not getting enough sleep, my mind just doesn't feel so sharp. And things that would take me a small amount of time, ends up taking way longer. Not to mention just not being able to focus in general.
Oh and be careful on eating out too much. Try cooking some of your more favorite foods, like a steak with steamed vegetables and/or a salad. Or something else that you enjoy cooking. I find if I just eat that junk at fast food restaurants too often I'll feel very sluggish and low-energy.
Also therapist would do good. Or even just your primary care doctor. They might run some blood tests. I found out recently that I was anemic so started taking Iron. I am feeling a million times better. It's crazy how if you're low on something that your body relies on that your body will gripe back. :)
Oh and side note, meet up with a friend or friends in IRL. Its nice to talk to people outside of the online gaming community. Helps me alot when I'm feeling down.