its a tough thing to turn your life around... and if we've behaved badly, sometimes it's hard to let go of feeling shame or guilt.  
like most of us, you probably have more things to learn, seems we're never really done learning.
a couple of things for you to think about.
apologize if you can (sounds like you've done that).
make ammends if you can... put things right.  if you said something bad about a person, find a way to build their reputation.  if you negelected someone, find a way to do something they need.
if you can't make ammends to the people you behaved badly with, do something for someone else instead.  if you didn't take care of something you should have, find a way to help some other person who needs the care you can provide.
once you've put right all you can, and made ammends to the person wounded, or someone in their stead, that'll help some of it.
the rest you have to consider this: if you feel guilty, if you feel shame, what use does that serve?  does it keep you from doing that sort of thing again? if you've truly learned, you don't need that guilt or shame to keep you on the straight and narrow... if that's the case, you can let it go.  if you still need it a little longer to keep you true, maybe it's not time to let it go just yet. but perhaps you don't need to be quite so punnishing of yourself.
if you've learned, and don't need the guilt to keep you straight, then the purpose it serves is to punish you for having behaved badly... if you punish yourself past the need, it holds you back, keeps you from growing.  think of it like this... if you have a dog that pees in the house, and you teach it to go outside instead, what good does continuing to punish the dog do?  it makes it fearful and withdrawn or mean.  it doesn't make it happy and useful and willing.  at some point letting go of punishing guilt and shame will free up energy for you to be wonderful to those around you.  
so if you still need your guilt and shame to keep you on the path, maybe there's more work yet to do on changing your life.  and if you don't need it to keep you on track, maybe it's time to let it go so you can be more loving in the world.