"Ugh. I'm depressed." We've all said it, and even the most happy-go-lucky among us will have an occasional bout of the blues. Sometimes it's the big stuff that triggers it—like getting fired, losing a loved one, or splitting up with your spouse—but often enough, feeling low can come from things as simple as a Grey's Anatomy rerun, crappy weather, or a rough night's sleep. But does that mean you’re actually depressed? Not so fast. (Looking to improve your mood? Prevention has smart answers—get a FREE trial + 12 FREE gifts.)

For most of us, these feelings come and go. But when sadness persists for more than two weeks and affects your ability to function at work, at home, or in other aspects of your life, you may have what's known as major, or clinical, depression. According to the National Institute of Mental Health, depression is a serious mental illness that affects about 17 percent of all adults during their lifetime.

Unfortunately, distinguishing between a rough spell and clinical depression isn't always easy. Take our quiz and find out if you're just temporarily down in the dumps, or whether you may be more seriously depressed—and learn what to do to turn around your mood.

Everyday decisions—like how to spend my Saturday afternoon—are…
Almost impossible. I never know what to do, where I want to go, or how I should spend my time.
A challenge sometimes. I’m a bit of a waffler.
No sweat at all.
 
Bed time can be soothing or a source of dread. Lately…
I have no trouble falling asleep but awaken at night unable to drift off again.
I fall asleep pretty easily and sleep soundly.
I tend to toss and turn before falling asleep, but usually sleep through the night once I do.
 
Lately, getting things done at work has been…
Up and down. Some days are definitely tougher than others.
Honestly? I’ve been calling in sick because I find it overwhelming.
Solid. I haven’t had problems completing assignments and focusing.
 
Right now, my house is…
A total zoo, but it’s always that way because cleaning has never been a priority.
Messier than usual, and it feels as if I can’t get it under control anymore.
Immaculate. I love a clean, organized home.
 
Recently my weight has…
Gone down because I'm eating better and getting more exercise.
Dropped by a few pounds for no apparent reason.
Gone up. My diet and fitness habits aren't the best.
Basically stayed unchanged.
 
When I first peel my eyes open in the morning, I feel…
Too tired to get out of bed, so I hit the snooze button and sleep another hour.
Somewhat refreshed. I dawdle, but then get up and start my day.
Energized and ready to start my day. There’s so much to do!
 
When I look into the future, I see…
Obstacles, obstacles, obstacles.
Tons of things I want to do—if only I had the time.
Not much. I don’t really look into the future. I just try and focus on today.
 
I feel down in the dumps…
Often. I frequently feel as if I want to cry.
Every now and then, when something happens to make me sad.
Sometimes, for no apparent reason.
 
When it comes to my free time…
I have a lot of hobbies and interests—but not enough time to get to all of them.
I’ve never had a lot of hobbies and interests, but I keep busy.
I used to have several hobbies and interests, but no longer enjoy them.
 
Sometimes I get these weird headaches and stomach pains…
Yup
No, not really
 
My patience levels…
Have plummeted. Basically everyone and everything is getting on my nerves.
Are fine. I don’t usually let other people’s stuff get to me.
Are varied. Slight annoyances can definitely ruin my day.
 
When I look back on what I’ve done so far…
I wish I’d done more with myself.
I feel guilty that I didn’t do more for my loved ones.
I have a few regrets here and there, but overall wouldn't change much.