So often we look at our past so much that we forget there is a present and a future as well. What has passed can not be changed, focus on the present which will in turn make your future better. The only person you need forgiveness from is yourself The law of karma is absolute and can not be altered. Only Guru Sahib have the ability to alter one's karma. Start by taking a a deep breath in and along with this, saying (in your mind) WAAAAAAHEEEYYY and as you release your breath say (again in your mind) GOOOOOORRROOOOOOOO. There, you are well on your way already