I Have Been Depressed For a Little Over a Month.

Hi, I am 17 and I have been depressed a little over a month and it was pretty severe at first, it made me think I dind't love my girlfriend anymore. Then I slowly felt better and everyday seems like a blur and recently I have been feeling guilty about lying to my gf about somethings. Not big heavy lies but small little ones that I never even worried about before till now. And everything else bothers me, even small little things. I am always thinking bout bad stuff and I feel like I will never get out of this state. I feel like I am ruining everything between my gf and i. I just can't stand it anymore. What should I do about the feelings of guilt and worriness.