Loose motions right after starting an antibiotic are usually the antibiotic disturbing the gut, not a new infection, and it's a known side effect of this drug class. At your age with
diabetes, though, loose motions can dehydrate you faster, so this needs quick attention.
Next Steps
Please don't decide on your own whether to swap or stop the antibiotic, that call needs to go back to the prescribing doctor since the right alternative depends on culture results and your other conditions. Meanwhile keep sipping ORS or clear fluids and watch your blood
sugar more closely than usual.
Health Tips
Go to a doctor the same day if the loose motions continue, you pass very little urine, or you feel weak or dizzy.