First, don't get hung up on the bipolar 2 thing. It's not a diagnosis of being bipolar, it's a description of the way many people manifest their depression. It's a controversial diagnosis in the profession, and was probably invented by pharmaceutical companies to sell more antipsychotics. You're depressed, and depressed people get thoughts they either don't want or that only bother them because they're depressed. Everyone gets thoughts. In that sense all thoughts pretty much come out of nowhere and so could well and accurately be called intrusive. The term is used to describe thoughts we let bother us because we're anxious or depressed and that's the nature of the illness. You've found some meds that are helping, but are you in therapy to see if you can actually fix the depression? No guarantee that will work, but if it does, these problems will be fixed, not just medicated. Depression and anxiety make many of our thoughts change from normal and interesting to frightening, and it also causes us to conjure up such thoughts. If we can stop thinking this way we can't be either depressed or chronically anxious. But it's a hard disease to beat. Keep working on it, but there's no magical way to fix it, it takes time and work. Peace.
So, my dear friend was diagnosed with bipolar 2 or atypical bipolar. It's hard but is treatable. Once they drilled down and gave her that official DSM diagnosis of bipolar 2, the plan to treat was better! Please know that!! I like this article that describes 1 vs 2 and things that may be unique to your bipolar with this diagnosis. https://www.medicalnewstoday.com/articles/319280#how-does-bipolar-ii-disorder-differ-from-bipolar-i-disorder Everyone is different though and have unique issues. Obsessive thought is difficult.
One of the most important things is to make sure you are working on the bipolar symptoms. Take your medication, keep your therapy appointments. Stay on track! Being really in tune with yourself is so important. Mania is something that kind of feels good, right? But it is when we make risky choices. And depression always feels horrible. Keeping on top of it and trying to have less swinging and cycling is a good goal. Do you keep a journal? I find that is really helpful.
Obsessive thought is something that can plague us. I understand. I know that i have cringe worthy moments where I just kind of shut my eyes and think "oy". But I can distract myself from it. we all have moments like you describe where we wish we'd made a different choice or we wish things went a different way. Our rational side knows that WE feel that moment and no one else cares or probably judges us for it but ya, we still focus on it. Maybe talking through that with your therapist would be helpful. Overall, thoughts are just thoughts. Try not to give them more life than that.
However, you know you are not alone. Intrusive thoughts are actually pretty common with bipolar. Most who have bipolar have the issue of obsessive thoughts and my friend tells me that they can switch. Obsess over one thought for a couple of weeks and then she will begin to have another one. My friend has found CBT therapy to be beneficial for the intrusive thoughts. Mention this to your therapist -- assuming you have one. I've been told to acknowledge anxious thoughts. Don't deny or just push away. Say, yes, that's bothering me. Or yes, this is on my mind. Then visualize pushing it to the side. It's there but you have other things you need to do and will deal with the intrusive thought later. Does that make sense? It's one way to get things done and not be 'stuck' by the thought.
Would love to talk more. Let me know what you think!