>>6
Can't you write her a letter telling her how you feel and your reasons? If so, do it, make it honest and heartfelt. Don't do it to get her back, do it to ease her hurt and devastation.
Also, if you feel so guilty over hurting somebody then you should attempt to stop hurting things. Don't crawl into bed and hide, learn from your mistakes, figure out how to stop the hurtful behaviors and do that. Don't just start hurting yourself, that is the equivalent of a mother hurting her baby, the worst thing you can do.
The thing is that guilt sucks you into self-destructive behavior and that just hurts the world even more. If you are not able to get up and make your business a success, let her go, and learn from your past mistakes then you are a bad person. Sorry, but you must break the cycle of badness, ruining yourself won't do anything good and will just hurt everybody more.
Maybe she has gone forever, maybe you broke her heart. You can atone for such sins by making it your mission to do good in the world, for everybody you hurt in your past, make five feel good. That won't ease the sadness but it will stop you from being useless and compounding it.
If you have done something hurtful and driven away the person you love then you must accept it and spend your life trying to never hurt anything again.
I hope you understand my point.