For me the diagnosis is not an issue, if you identify with BPD then it does not matter what your therapist says. From my understanding it is really only a psychiatrist that can diagnose you anyway. Whatever labels your therapist uses should not really effect your therapy in any way. A lot of therapies use CBT which should help you in some way. If you are interested in DBT then a good website is DBT Self Help

Oh, and welcome to the group.