There is a good book called Feeling Good by a doctor David Burns. I would suggest that you get that book and read it. It really helps explain depression and is very informative.
If you aren't feeling rignt, not happy, well then you are most likely depressed. If you are questioning it, you are most likely depressed. I would talk to a doctor and explain what you are going through and maybe get a physical to make sure that there is nothing else going on. Depression is a beast. You need help and support if you think you are depressed. You will feel sad a lot of the time, probably be crying for no reason. There is a lot that goes along with it, lack of energy, aches and pains, though not always.
Keep posting, there will be others along with more advice.
Take care my friend.
Moderator-Depression and fibromyalgia
fibromyalgia, Chronic fatigue, depression,allergies