You are human, I am human, we are all human - we do things that are wrong, mean and hurtful. It is right to want to do better, it is right to want to apologise for when have done wrong, to somehow make it better, to feel regret over the things we have done that hurt others. This is what it is to be human. But all we can do is make the best choices that we can today, and do the best by those in our lives.
The bipolar is no different - you can only do what you can do, take your meds, try to keep stable, recognise when you are being oversensitive and try not to take it to heart, recognise when you are being selfish or callous and try to not be nasty....
We all make mistakes, and will continue to make mistakes - the trick is to try and make less mistakes