It doesn't seem to have come out of nowhere though. You were told from the onset that your CBT therapy would be time-limited. Just recently your pdoc (I believe) gave the opinion that you would be served well by DBT, and you shared that information with your therapist. You have been in crisis and have had to have hospital intervention a couple of times fairly recently because of SI (maybe suicide attempts, not sure) which is perhaps a strong indication that the CBT may not be the best therapy for your current issues (which is why DBT seems to have been recommended). It sounds like all of this is coming together and your T feels that your pdoc's recommendations may be best to follow since you have placed your safety in jeopardy several times recently under her care with CBT. She really has to do something different or your safety will continue to be in jeopardy. Honestly, this doesn't seem like a surprising move. DBT probably is a better therapy match for the kind of issues you are experiencing, and your T is doing what may need to be done to best help you and keep you safe.