I either really put all my effort or just dont give a damn.any advice?

and i think that its taking a toll on me & my life. for example if i have a project that i dont get i'll just give up on it completly or if i'm having a bad day i'll just be like " eff this" and like a few hours later i'll be all like "i can do it" so i'm just wondering what i can do to eradicate this habit and not be so extreme with my moods.