Yea your symptoms are vague in that many things can cause them. From sleep deprivation, diabetes, hypothyroidism, undiagnosed sickness, depression, stress, etc. I think the list could be longer.
I think depression once other physical issues have been weighed out, can mimic many physical maladies. At least it has for me. I don't have any chronic or deep depression but I do have bouts of moodiness. I'm narrowing it down to my own health reasons, stresses at work, stresses at home with my wife, and the things I do to myself to make things worse.
But please seek the advise of a doctor about your issues as there is a lot that can be done to help a person. We want you to be better for sure!
you have vague symptoms, but a good start would be to have your thyroid checked. An under active thyroid would make you fatigued even irritable. The thyroid controls your body's metabolism. So imagine if you are under active, everything slows down in your body. You are advised to see a physician who can run labs to rule this out. Wish you the best.
These are typical symptoms of depression, but you need to see your doctor to rule out other causes first. If everything checks out okay then make an appt. to see a psychiatrist and go from there. I suggest a psychiatrist because they are most knowlegeable should you need medication to help with this. Let us know what you find out, we do care and understand. Best wishes!