How long was your first antibiotic treatment? SIBO is often treated with a three-month course of antibiotic. I used doxycycline, and managed to get through a bit over two months before the bellyache side-effect caused me to declare success. If undertreatment (too short a course of medication) is the reason you’re having a recurrence then there’s no reason to fear a life-long affliction. A low FODMAPs diet should be perfectly okay forever, if that’s what you choose. Whether it will be the thing that prevents SIBO from recurring is a tougher question.
Good luck!