Both are caused by seasonal changes (in this case, light and heat) that can disrupt the internal clock responsible for your sleep and hormones.

If light's your issue, stay inside as much as you can, or try to force your body into a strict pattern: a half-hour of light each morning (around 6:30 a.m.) and a consistent bedtime. For heat, crank the AC and take cool baths. Since SAD is annual, see your doc next spring to ask how to proactively treat your blues.

This article originally appeared in the July/August 2017 issue of Women's Health. For more great advice, pick up a copy of the issue on newsstands now!