TMI Antibiotics side effects

I’m 23w FTM I had a the very first UTI in my life and was given an antibiotic. Day 8 out of 10days treatment I had diarrhea that was better the next day. Today it’s getting worse (frequent and watery) and I’ve never had diarrhea in my life so not sure what to expect. Sorry tmi

I’m drinking plenty of water and watching what I eat. I also talked to my dr and he gave me more antibiotics for the diarrhea.

Did this happen to anyone who took antibiotics? How severe was it?

Appreciate any reply because I’m very anxious.