I am bipolar 1 with psychosis and for about 3 months was convinced I was BPD instead of BP1. Kind of embarrassing but I guess it's not so uncommon as I have a long history of denying my diagnosis. Any way how I finally got out of it was to examine my history. Realizing that I can go for periods of weeks, months and some times years at baseline. Also, I believe I was indeed stuck in a mixed episode during my BPD days lol. I tend to get delusional at times and well, long story short was convinced I was BPD+NPD!

What I suggest is to look at the big picture. Retrace your own history going back as far as you can. One of the main differences between BP and BPD is the duration of mood swings. Also with BPD it's usually going to be depressed, irritable, angry and baseline. And you can cycle thru all that in hours each day. Even in my most rapid mixed states, my moods tend to last much longer and also accompanied by some level of delusions. Also I get very elevated to a point of feeling like I had some cocaine.

Also I did lack some key signature traits of BPD, no abandonment issues, no SI, no splitting. Also I really have not had much trouble in relationships. My current one I've been with the same woman for 15 years.

I don't know what you are, but am advising you to look at the bigger picture, it may help you too. I been struggling with my diagnosis since 1989. It's easy to focus on some other illness and say, "yup that's me" without looking at the bigger picture.

Good luck to you!