Under no circumstances should you be giving antibiotics to an 8 month old other than on a physician's orders. Antibiotics interfere with cell reproduction,. Somewhere along the line someone should have taken a culture to identify the specific strain of bacteria.
Hello, it looks like it's your anxiety playing huge role in this.
Why did you give it to your son by the way? Some antibiotics are restricted for people from certain age group.
Regarding the stomach issues, they are very common side effect of antibiotics. Just stop taking them once your course is done, and repair your body's immunity with probiotics, or natural probiotics like cultured yogurt or kefir.
My personal advice, out of personal very very bad experience, if your doctor gives you a new medicine every visit, you might want to change him, especially if he's giving you a lot of antibiotics.