Flowers. Plants overall. Both buying or receiving cut flowers or potted plants, and pottering around in my own potted garden (ha ha).
The colour green. Partly because of the above, partly because of its harmonic calm feeling without blues coldness, and partly... have you ever read Kim Stanley Robinson's Mars trilogy? In it, there is a reference (ok, several) to 'the white and the green' as opposites (that can merge and mix under certain conditions). To me the white represents something clinical, sterile, scary, while the green is living and crumbling at the edges and changing and happy and nurturing.
Locking myself up for a week with the necessary food supplies ready, reading, crafting, watching tv shows after they were originally broadcast (maybe catching up on entire seasons in a week), eventually cleaning and tidying my surroundings when my energy levels rise.
Ventilating. Talking about anything and everything with someone I trust (mainly H).
Because someone are bound to think it unless I comment: Retail therapy does not, maybe surprisingly to those who know me medium well, belong in the above. I only shop when I am doing fine and my energy levels are well enough for me to get restless.