I would tell her about Joan and how you feel she acts. I wouldn't assume bipolar yet because giving a name to that other side of yourseolf could be a personality problem or a blend of something like a combination of the two. There are all shades of mental issues and illnesses so unless she is able to observe you in another state than she is used to than all you have is the memories of that episode. The only thing to do with that is be mindful that you can be back in another episode like that but I would try to continue on with my life and the work that you are doing with you are doing with your therapist right now in order to avoid spending too much time hoping or trying to bring Joan to the present. If she is necessary she will come back.
First of all, if you're going to a professional, they're going to be able to tell if you're malingering. Secondly, if you don't tell them everything that's going on in your mind how can you expect them to help you if they only know half the picture?
You have to just let it out, just like you did on here. Sure you're going to be making yourself a little vulnerable but sometimes that's what it takes. Once you unload it all, it'll be a lot easier from there on out. I think we've all been there!
You should tell your therpist about these symptoms you're you're likely to be bp1 as you experience hallucinations
You know those sayings: "Tell it like it is" or "Give it all you've got" ? It's not clear what circumstances were at hand when these catchy phrases developed, but they have your name written all over them.
When you tell your therapist every thing that you are going through, she can get out ALL her tools to help all of you. As long as you feel you're in a safe, confidential environment she's probably the best one to open up to.
If talking were to be an obstacle, bring in what you posted here. You wrote it beautifully. It was to the point. And you requested help.
When you express your needs, you're more likely to get them met. I think you'll feel better approaching your thoughts & being open to help. Just tell it like it is. Be safe.