Sea buckle athletic

Penicillin V and Flucloxacillin? - penicillin given for which infection

I was prescribed erythromycin and gave me severe stomach pains, so I asked my doctor for pills and had a different time, penicillin V and flucloxacillin 250mg four times per day.
I was wondering if anyone have any idea what kind of infection and / or what to take even more important than I thought I was a close first game to reduce the risk of gastrointestinal disease had (instead of 500 mg every 5 / 6 hours).
Thanks in advance