I used to have this issue a lot with my current research, but I think its just developing other identities/hobbies from my scientific career/interests which I've done a lot of since graduating and working a bit as a research associate.
You already know your science super well as evidenced by your invites, everyone deals with imposter syndrome, but most importantly, its good to just remember you are a person outside of your PhD invites and your scientific work and have things you enjoy
Also maybe morbid but the phrase "memento mori" and stoic philosophy has helped me deal with a lot of things with regards to regrets about doing X vs Y, being in a certain place in life, etc. The reminder of death is actually kind of comforting in knowing that in the end, what's more important is to live a fulfilling life filled with enriching experiences, which usually means that a lot of things I am anxious about I find tend to pass regardless.