S.I. doesn't mean you messed up. It doesn't mean that you have failed your parents. They are there to take care of you and make sure that you grow as a person, they should therefor be there to help you. Being the best is a very tall order to fill, and mistakes happen. However it's not the mistakes we make, but how we deal with them.

S.I. can mean that you are hurting in some way or another, just take it one day at a time and do your best to get better. For yourself. You are well worth the love of your parents, and you are well worth the love of yourself.