Failed my Science test?

I just found out I failed the constructed response part of my test. It was worth 50 points. I got a B on the MC part but when ever I fail a test or screw up homework of whatever I start tearing up and before I know it I'm full out crying. I get depressed. I studied so hard! I feel like a loser, do I just not deserve good things in life? I have so many bad thing happen to me and it just tears me down. I can't stand how my twin just goes through life without a care and does good and I actually have to try to do good. The mooches off everything I do! I'm so sad and depressed now and am crying. Please help