I can relate to feelings of shame and feeling like I have let other people down. Mostly my feelings of shame are directed towards myself though, even when it does not involve a feeling of letting others down. I am my own worst enemy.

Sometimes self-help sources, like exploring life coaches on youtube who occasionally do videos on self-acceptance that could be helpful or books. Therapy helps to explore exactly the route of these feelings and how family dynamics often play a role when it comes to these feelings, especially shame. I also believe that with Bipolar mania, it leads to things we regret, and then feelings of shame kick in when crashing into depression. All you can do is keep moving forward. Usually we are much harder on ourselves than we should be, although it is always good to learn lessons as mistakes come our way. Try not to be so hard on yourself. I know it's hard and realize you are not alone.