Antibiotics are used to treat bacterial infections. Most of the simple infections we get such a s common cold, cough , sore throat are usually viral and they are self limiting which means they resolve after few days with minor treatment and antibiotics are not needed. In your case your doctor had asked you to take the antibiotics after 3 days if no better, since you’ve started feeling better you should have not taken any antibiotics. Now that you’ve been taking them, the dosage you are taking is not right so there will be chances of developing antibiotic resistance, in which case the same antibiotic will be less effective when you actually need them. So you don’t need to take them anymore but from next time pls follow dosage instructions correctly as directed by your doctor and also avoid inappropriate use of antibiotics.