I always take antibiotics with food but i'm wondering how much food is considered enough so it won't irritate my stomach?

Regular meal: Basically if it is indicated to be taken with food you can take it with your regular meals. If it is an antibiotic that you take more often than your meals take a snack.

Enough food: would typically be the amount you would eat in one meal. I usually tell patients to take their antibiotics at the same time every day with their largest meal of the day. Check with your doctor if you are still concerned with intake and dosage of your medication.