Not sure I am adding anything of value to mammo's excellent post, but I have had to take doxycycline for Rosacea and am alway uptight when it is suggested, as I very often get serious diarrhea from antibiotics.
For me, then, anxiety is always high when an antibiotic is prescribed. Phobic about the medicine. I never experienced anxiety from this medication. I think I may have been on an SSRI a few times when doxicycline was recommended....
Do follow up on mammo's advice. Good luck!
Thanks so much for the advice