Be honest with me does this sound insane?

[Walker]

I just feel extremely bad for making other people feel bad and in my mind I feel like it would be an insult to them if I were to feel any form of happiness or attempt to improve my life. If they don’t want to forgive me, why should I forgive myself?

Just by feeling as crap as you do, you've proven that you are worth being forgiven for whatever this is that's gone on with others. You don't need to punish yourself for these things as A) that serves no purpose and B) you have no idea how these people even feel about this now. Are they still upset over anything that has happened? Have they thought about this any time recently? Are these new things you've done? I just don't think that there is any value in flogging yourself over something that has happened. It's in the past now and if these people aren't in your life to experience the moments with you then it's time to move on. Improving your life is the perfect way to 'pay someone back' for treating them badly, in my opinion. Doing well and getting on with things without repeating the behaviours.