Ah, not half full or half empty, just half?

I think you need to find another, "stronger" emotion to work with. Is there any fear you'll be stuck this way? Looking for a way out of fear sometimes points me in a direction toward finding a more comfortable way of being. Are there things you especially don't want to do (why especially? I'd try doing some for the feeling of ?).

I'd look for a positive thing I didn't want to do but would like done, for me it would be change-my-bed, I enjoy clean sheets, and I'd do it anyway and see if the satisfaction of the opposite could provide a momentary spark of happiness? It's not something that would remain but the feel of it might get my molecules moving more in that direction, seeking that out again? Providing something for myself that I want is a form of happiness. I've made myself tell me what I "want" and then gone and gotten myself that and the getting both distracted and showed me I could provide for myself. Let yourself provide for you. You want some happiness, tiny thing would make you happy right this minute? Decide on something (only you can know what would make you happy) and go after that.

I don't think having houses, jobs, money, therapy, health, etc. make us happy, they just support us as we look for the things we enjoy. Your painting only supports you now (which is fine) there is no "should" enjoy it or should enjoy music, etc. Nothing outside of you can tell you what you "should" enjoy! And happiness doesn't necessarily correlate to thankfulness either. You can be thankful for what you have and are doing and how well you're getting, etc. until the cows come home.

My husband asked me a few moments ago did I want breakfast. I asked could he make French toast? and he did and delivered it to me here in my chair while I was typing this post. French toast and sausages with too much syrup. For me, today, I don't anticipate it getting much better than that :-) But something "good" has happened to me today, makes me feel good and I'm filled with the knowledge and hope that something else good could happen to me today. I know myself and have my idea of "good" and my self and life try to match that as often as it can.

So, do some exploring and see if you can find your idea of good/happy? Don't pay any attention to what should feel good or should make you happy, find what does feel good or make you happy. I still like the example of Julia Roberts in "Runaway Bride" when Richard Gere accused her of not knowing how she liked her eggs and so she cooked up a couple dozen eggs a million ways and figured out how she liked her eggs. It's often that simple when wanting happiness I think.