Antibiotics are drugs that are used to help the body fight off infections. We use them only when we feel that the body's own defenses will be inadequate to clear an infection, or if we feel that those defenses will take too long. It sounds like you have had 3 separate infections for which you used antibiotics. The antibiotics you likely took for these infections are most likely very mild, and are unlikely to harm you. In addition, only 3 small courses of antibiotics are probably not enough to do any harm.
It is true that stronger antibiotics that are taken for longer periods of time can be harmful to the body. They are harmful by killing off the good bacteria in our large intestines, and by allowing more aggressive and harmful bugs to populate our bodies. This negative effect of antibiotics is something that is mostly seen in people that have had major infections that required intravenous antibiotics in a hospital. I think the courses of antibiotics that you have had are unlikely to do you harm.
I suggest that you schedule an appointment with your primary care physician
. Bring up the issue of the antibiotics with him or her. As long as you are not showing any signs of infection, or symptoms such as diarrhea
, there will probably not be much cause for concern.