I’m also having dreams that I think might point to me being fictionkin, but I don’t know how to explore it further. I’ve tried watching the series that aligns with my dreams but I didn’t feel any immediate familiarity, only a nagging sense of “this is relevant somehow”. Do you have any suggestions for what I can do from here?

I do have a few suggestions as it happens. Try watching other series that share common elements from the one that you think aligns with your dreams- it may be something similar but not quite it. You could also look at fanfiction for the series, as it may be closer to what you remember. 

Another path I urge is meditation and self reflection. Put aside outside influences for a while and look inside yourself, and see what more you can glean from what you find there.