Thank you for writing. I’m very sorry life has been so challenging for you for so long. I’m very, very glad that you have a therapist and that you have shared enough of your history with your therapist that she is aware of your struggles with dissociation.
To answer your question: Of course you should share your latest concerns with your therapist. Your therapist only has what you tell her to go on. The more you share, the more helpful she can be. Therapy is a collaboration. You deserve to get the best help your therapist can give you. Your therapist deserves to be told what worries you so that she can offer you the support and guidance that you need. Without that kind of honesty and frank conversation, therapy can only be minimally useful.
DID is a protective response to overwhelming trauma. Untreated it can take on a life of its own. Treatment includes honoring the protective instincts but then helping you learn other ways to take care of yourself that don’t depend on you splitting off from your core self.
Please — give your therapist the material she needs to help you make more progress.
I wish you well.