It takes time to adjust to the diagnosis. This is a lifetime diagnosis. There is no cure. There are methods to manage it, but it is something that never goes away. Because of this I would think it is fairly normal for it to take awhile, even years, to come to terms with it. Don't beat yourself up because you haven't come to terms with it yet. Give it more time.

I also suggest a different way of looking at things a year ago. Don't look at it as when you didn't have BP, instead think of it as when you didn't know you had it. While it is possible that you didn't have BP a year ago, more likely you did and just weren't diagnosed yet. Then you didn't have a reason for certain moods, symptoms, or behaviors or the knowledge of how to deal with them. Now you know what you are dealing with and have some tools on how to do it. Now you also have ways to try and manage the symptoms to help minimize them. With the diagnosis you gained more control over what you are dealing with. The diagnosis isn't when the BP started, it is when you decided that you were going to take control of how you were feeling.