Self Doubt/Really struggling…

So much self doubt that I will survive these suicidal urges. Even my therapist is really worried about me. I can’t get suicide off my mind. Lately some issues have resurfaced that have caused me to start burning again and have me thinking of suicide almost constantly. These issues include relationships(romantic),fear of abandonment/rejection,boundaries,self hatred,etc…I keep having dreams/nightmares about suicide and think about suicide all day long. I watch videos on how to do it,videos about people who have committed suicide,videos about people who have survived suicide attempts and listen to songs about suicide. Several times lately I have had the knife to my wrist ready to kill myself. Obviously I have not done it. But I am really scared that one of these times I will not be able to stop myself. Sometimes these urges happen suddenly and can be very strong. I have been diagnosed with borderline personality disorder and also believe I am bipolar. I start dialectical behavior therapy in a few weeks. I do have an awesome therapist(Jessica) and have developed a strong bond with her and trust her completely.