Tips for moving back home?! Can you change your personality? How to stay motivated in therapy?

1. Any tips for moving back home after a few years? I'm moving home at the end of August and am kinda nervous about it. There's no abuse in the home, but I have a very overprotective judgmental mother who still treats me like a teenager (I'm 23), and a pretty absent father who would rather watch tv than spend time with his family, and when he does spend time with us all he does is yell at us. And my parents relationship with each other is pretty nonexistent. They never talk, and they act more like roommates than spouses, which is really hard to be around. I'm just not sure its the best place for me to be, but I don't have anywhere else to go. Oh- and I'm the youngest and will be the only child living at home. When I feel trapped in a situation, depressed, manic, feel lost with my life (which I do right now), or just generally when I don't have much else to do, I either act out sexually or cut. My mom knows that I've cut in the past (although she doesn't know about the recent relapses), but would completely lose her shit if she ever found out about the sex. I'm worried that being home and being around them so much is going to trigger me into wanting to either or both of these things. 

2. Hi Kati. I would like to know if there is a consensus in the mental health community about whether personality drives behavior or if behaviors determine personality. For instance, diagnosing someone as a narcissist is based on patterns of specific behavior, right? But do those behaviors only manifest because the person is a narcissist? I guess this is actually a bunch of questions rolled into one. Are people their diagnosis? Can Zebra's change their stripes? Can you save an important relationship with a person who has a personality disorder even if they are by all accounts a "toxic" person? Is someone weak because they can't let that relationship go, or are they strong by trying to show compassion for someone they love who has treated them cruelly? Hope you have a great day and thanks!

3. Hi Kati I have a question, I hope it's not too late to submit one. I have heard a lot that therapy is hard, but I think I finally realizing what that really means. I used to love going to therapy and look forward to having someone actually listen to me, but now I almost dread going. We are doing a lot of DBT work and my therapist assures me it will help, but it just feels so tedious! Any advice on how to keep motivated with doing all the DBT homework and maintain the motivation to even keep going to therapy?