Feeling a little more tired, a little less patient and a whole lot of blah? It’s understandable—the combo of colder weather and shorter days can dampen anyone’s spirit. But for some people, this time of year triggers changes that go way beyond a funk: Experiencing significant fatigue, feeling sad on most days and sleeping more than usual all point to seasonal affective disorder (or SAD), a clinical form of depression, according to experts at the American Psychological Association. The symptoms are exactly the same as those of major depression, and can include losing interest in activities, having a hard time concentrating, more irritability, cravings sweets and starches, and weight gain. The only difference is SAD follows a seasonal pattern, with symptoms starting in the late fall and early winter, and improving in the spring.

Get Outside
Take a long walk, even on brisk or cloudy days—and try to do it in the morning within two hours of waking up for the most benefit, according to the Mayo Clinic. Outdoor light can help ease milder symptoms.

Work Out
Physical activity can help reduce stress and anxiety, both of which increase SAD symptoms.

Ask About Medications
Your doctor may prescribe an antidepressant if your case is severe; he or she may also recommend starting treatment before symptoms typically begin, and continuing past when they dissipate. It may take several weeks to notice full benefits from an antidepressant.