Believers, I feel jynxed by negative people around. Help!?

Okay, so I was one of the brightest student back in high school and I managed to crack admission in a top notch school. Luck has always been on my side, through God's grace but things have changed ever since I entered sophomore year (Also the time I had my first relationship with this guy that ended just in about a month). My personal life is still okay with my friends and family but academically I have come down to a low profile, not typical of me. What astounds me is the fact that I am working as hard as I always used to. When I go for an exam, I blank out on the formulae; when I sit for a viva voce the professor aks the toughest question to me (even my friends agree to that); I've flunked 3 courses till now when I'm entering junior year. I didn't ever get close to close of flunking. I had the second highest GPA in high school out of all the students in class. Please offer me solace. Where do I head?