Hmm, perhaps a little depressed. Depression doesn't always have to correlate to a point or experience that makes us go downhill this way. Sometimes depression just is. I'm chronically depressed but have been off my medication for 8 months (after 5 years on!) because I couldn't afford them anymore. I find that after a relatively short period when I was very dark blue, I am coping and functioning well. Some things that I have found that help lift me up a bit:
A tidy house. Yes, I know very well that housework can be the crux of depression. Feel to down/bad/tired/etc. to do it, but then feel even worse when I look around and see the tip I'm in. I do one area until it looks nice and I would let a stranger see it. Then I stop. If I try to do everything, I get overwhelmed. It starts to spread to other areas of it's own accord. OR, tidy up one room, make it nice and comfortable, and hang out just there for a while until you feel a little more motivated to do any other space.
Get outside. Sun, clouds, rain, it doesn't matter. Fresh air and moving around make me feel much better. I am horribly fat but always feel like my head clears out when I've gotten out do do something. Anything. The other day I walked around our little town for two hours looking at things, that's it. I actually had a very nice time
But even if you don't think you really need to, give your doctor a ring and speak to them about it. They won't necessarily put you on ADs but may have better suggestions than I do.
Do you get any time at all just for yourself? If you're constantly caring for everyone but you it can certainly bring you down this way. It doesn't even have to be something big, you don't have to go out and spend money. I find it's very satisfying and rejuvinating to tell dh I am "off duty" and lock myself in for a hot bath with a book and a glass of wine.