This feeling I get - is it depression?

Suddenly I feel sick of life. I feel very lonely. I feel tired. I feel stressed out. I feel like quitting my job. I feel lost. I feel very very down... I juz wanna cry~ Sigh~

This feeling is getting to me increasing bad recently... for the past 1½ month, I've cried myself silly becoz I juz feel so darn upset. Somehow I keep feeling tat this job is not suitable for me, makes me wonder why on earth I'm in it... =(