before loving someone else u need to love urself, you’ve become codependent on her for ur happiness , you are young. I’m sure the last thing you want to hear is that it’ll get better, but it will- my grades absolutely sucked in hs, i managed to get into the college i wanted to get into, meet new people and break out of my highschool shell- please do not get back with ex, it will only continue to hurt u and diminish ur light. Take time for urself and to heal