21-Year-Old Medical Student Struggling After Breakup and Missed Opportunities - What Can I Do?

I was not all at studious till class 8.i used to rank hardly 45 th in a class of 50 students.Then in class 9,my teacher changed my section.When I went to the new section,I felt in love at first sight.This was my first love obviously (But one-sided).She was a topper and beautiful.I proposed her.She rejected me and told me that I am worthless and I have no future.I was very sad for 6-8 months.After that I decided to prove her that I am worthy and I can do something.I left everything (cricket,karate,dance, singing, drawing, swimming-I used to learn them but I left).I completely focused on to prove my love.I started studying for more than 10 hrs daily.I was just 8 marks behind her in my 10 boards.I cried a lot that I lost the battle.She became 6 th and I became 9 th in class in 10 th class.Then I gathered hopes again.This time I started studying as much as I could(14-16 hrs daily).I became 2nd in class 12 and she became 3rd.I got just 1 mark more than her.I know it's a great win.I have proven myself but I don't know why I can't move on from her.I have been in 4 relationship in 4 respective years (class-9 -10 -11 -12 respectively) but I am not finding any interest in these relationships.I am completely confused what is happening with me. Please tell me what should I do now.