Finishing PhD and didn't secure a postdoc position: how to proceed?
One option possibly available to you are academic jobs that are more teaching-oriented.  While (in the US and Canada) hiring for permanent teaching-oriented jobs is mostly over at this point, there is still hiring going on for temporary positions, both full-time and part-time, both at four-year universities and community colleges.

Such a position maintains an academic affiliation.  Not being a physicist, I do not know how taking such a job would be perceived if you apply for research-oriented jobs in the future.  I expect these positions (especially full-time ones) would be viewed positively in applications for permanent, teaching-oriented jobs.