Maintaining Identity --BPD Dilemma

I just recently found my old personality, after gradually losing it to a therapist, I sought treatment and coping skills from about 3 years prior. I finally saw a new therapist who saw quite clearly how boundlessness and open I was and spotted immediately my personality disorder, of which my other therapist didn't see.

So my question is how do I maintain my personality and friendships with other people without losing who I am again? The last 2 years have been an exercise in futility, and I find odd ways to abuse myself. Like riding my bicycle in traffic and working too hard. I've never cut myself, so I'm more covert in the ways I abuse myself. More manly things like working with tools and overworking myself way past the point of exhaustion and overexercising.

I've started journaling again, and this seems to help. But how can I keep boundaries between myself and others? I don't like when I get upset when I realize someones crossed my boundary and I don't want them their anymore. It's as if someones constantly waking me up from a good sex dream! haha. Funny, but I think it shows clearly how frustrating it could be.

Also does anyone have any success with medication? My first thought is for the anxiety.

Only way I've figured out is to isolate myself. Not healthy and not helpful, I'm sure.

I suppose the first step is to very clearly define what your boundaries should be (with your therapists help), and be vigilant in keeping them in the front of your mind when dealing with others, and to remember to make them override whatever emotions you experience that make you lose sight. Easier said than done, I'm sure.