What is the best way to get over a pretty bad heartbreak?

First tell him how you feel because all these pent up emotions is really just you being confuse on what happened wrong. If you can't tell him upfront email him or text him. Then just ignore him for a few days or even weeks until you've recovered. Give it some time after all time heals everything ;P You'll make through and besides it's your last year enjoy it don't let one person ruin your HS moments ;P