I am not great with mistakes. I used to be very very bad with them, to the point that if I tried something, and made even the slightest error, I would never try it again. Suffice it to say, I ended up doing nothing.
I am much better with it now, though I have to pick and choose my battles. When I try something new, I do it on my terms, when and where I can manage it. I also let myself "feel" the pleasure of doing it when I find something I can do reasonably well. I have difficulty stopping all the negative chatter going on in my head. Trying to "talk" your way out of the negativity is hard but works to some extent sometimes. I have found the best way is to "feel" your way out of it. A feeling of happiness will cut through the negative chatter like the sun burning up fog. The problem of course is being able to "feel" happy, which I think was my problem in the first place. It takes practice, but I do much better with it now, and I am always looking for little things to make me feel a bit of happiness. The slightest little good thing can work, just making my bed in the morning helps sometimes.
All the bad things used to wash out any feeling of happiness, even if there were some good things in my life. Now I take just one little good thing in its own context, and let myself feel a little bit of happiness. I don't have to feel it all day, just for that moment. Sometimes I think its futile, but I've come to trust that every little bit of happiness will help, even if it doesn't feel like it at the time.
Of course if your mistake has affected someone else, then that's harder to overcome. Most likely you will have to make amends in some way before you can believe you deserve to be happy and move on. But keep in mind that everyone does this from time to time to some extent or another, so try not to be too hard on yourself and keep things in perspective.
I also have come to realize that everyone else tries their best to hide their own mistakes. So do not fall into the trap of trying to compare yourself to other people, because you do not, and will not, know exactly all the mistakes they have made. The old saying that the grass is not always greener applies here. I used to think everyone else had it easier and they do everything so much better than me. NOT TRUE. Not true at all. I don't care who you are, it is simply not true. The longer I am around this earth the more I am convinced of that and thank my lucky stars. Of course people told me this a long time ago, and I didn't believe them. So all of my ramblings here will probably not make anyone believe it. But saying it helps me, which means I've helped at least one person, and that makes me feel happy.
Whoo hooo!!!