Cutting is a commonly in Borderline Personality Disorder which can look a lot like Bipolar disorder. I recommend you look at the Borderline Personality Disorder guide on this site. (If you can't find the borderline stuff - go to the forum page where you click bipolar, scroll down to Personality Place and in the small print you will see borderline - click that)
I was diagnosed bipolar over 30 years ago (called it manic depressive back then) - but denial kept me from focusing on how my life might be affected if I didn't continue treatment, listen to professionals or take medication. The outcome of denial for me was 3 marriages, 2 unfinished college attempts, over 20 jobs, 2 children raised dysfunctionally, multiple car accidents - confusion, anger, rage, poor credit rating (spontaneity). Multiple times going back to shrinks, just to have them all repeat bipolar every time. I got really angry with them always telling me the wrong thing! I didn't want to be bipolar, and if I was they needed to just fix it that day!
All that is past me as of 6 years ago when I couldn't deny the truth anymore. My bipolar mental illness seriously affected my life. I thought it was the worst point when I lost that last job (fired for acting unprofessionally) and it took a huge lot out of me these last years. I got so bad I was agoraphobic for 2 years, I missed my first born sons wedding, I gained 50 pounds.
It was absolutely worth it (well not missing my sons wedding, but everything else)
My point is - don't deny the issue or try to make light of it. You are very lucky, now you can begin to own your emotions - not control them, but understand them and understand how to reduce spontaneous reactions.
You are the same wonderful person you were a year ago.
Trust your professional support staff - and utilize them.
So far, my story now is much better. For the first time in over 35 years I like me.

I hate my weight, I still have issues, I am still getting better but I have a lot to get past. Not just the past 6 years, but the 28 years before that which I squandered. If only I had stayed in treatment and respected how much my illness was with me. I mourn my lost life, and constantly tell people here - especially the young - how lucky they are to be getting treatment.
LettinGO - time is in front of you. You will have med changes til they get it right. You will step forward and slip back. But stick with it. If that time is passing anyway, don't you want some part of your life to be happier? That is what awaits you. Clarity, understanding, self acceptance and knowledge. PsychCentral is a great forum for sharing and being with similarly experienced people. You are lucky and very welcome here.
Best of luck to us all.