I've definitely treated people in bad ways that they did not deserve. The best thing you can do for it is do everything that you can to be well and stable and be a good friend back to them. some people will leave you because of it and others will accept it as part of your illness... I can understand both positions because the hurt is real even if it was due in part because of the illness.
Cherish those that stand by you and appreciate them for what they have put up with.