Depression is not a binar sickness it's a sloping scale. I was diagnosed with dysthymia/anxiety. It's a milder form of depression. I also suspect I have ADHD but I have never got a diagnose for it since it haven't been a huge problem for me.
http://en.wikipedia.org/wiki/Dysthymia
I also wondered if I actually had a depression. I would be fatigued, didn't do chores because i didnt have the energy, didn't do my hair or washed cause I couldn't be arsed. On the other hand I could go to school and work out and my appetite wasn't affected allthough sex drive wasn't all that hyper.
Sometimes I got double depressions and sometimes I felt very happy. As I said I wondered if I was depressed or not and it seems I actually wore when I went to the doctors. I got some medication against it (Zoloft which is a SSRI). It made a tremendous difference in my well being. It was like turning on a light switch.
Since I've had this so many years I found what worked well for me and what didnt work.
If I were you I'd:
1. Go to the doctors office and fill out a depression/anxiety spreadsheet. You'll probably be surprised by the results. It was first when I put it on paper I realized how I actually was feeling.
2. If there is a tendency towards depression or anxiety then get treated for it with medication and or a therapist. If you get medication then follow the regime relentlessly. It might take several months before the real effects kick in.
Self care
3. Always make sure you get enough and good sleep every night. This is very important. A good nights sleep can reduce fatigue a lot. Don't overwork your brain just before you go to sleep and don't have stimulants several hours before sleeping.
4. Work out several times a week. It sets you on the right track and gets you out of the house.
5. Reduce the junk food and candy intake. Sugar can make you sluggish.
6. Stop watching porn, it can have some pretty bad psychological effects.
7. Get out of the house as much as possible. If you are introverted like me then your home can become your prison and safe haven at the same time. Too much alone time is very bad.
Either way I hope you get well.