I've had it with both myself. Personally it's stronger when I'm manic

i have had paranoid delusions both manic and depressed but i experience it the most with mixed episodes.

I get that feeling when I’m anxious, as far as I know I don’t have BPD

Yes! They can happen in both. There's also a disorder called schizoaffective where it's a combination of bipolar and schizophrenia. There's a fantastic book called the collective schizophrenias. It's written by this woman who struggles with this and academia and all that jazz. It's spectacular and i recommend