I'm depressed. I lost my job.

Cheer up! You'll get a new job.

I feel blue./I feel low./I feel really down.

I've got the blues today.

I feel down in the dumps today.

No one understands me. It's depressing.

Don't talk like that! I understand you.

It's sad. 真可悲

It makes me feel depressed.

Rainy days get me down.

Rainy days make me sad.

I feel blue on rainy days.

I don't feel like doing anything today.

Come on! Let's get moving. 好了,快点儿

I don't have any enthusiasm for life.

He looks melancholy. 他满脸忧愁

He has a melancholy look.

He looks gloomy today.