All antibiotics can in fact have bad side effects. The problem is that they kill indiscriminately, meaning they not only kill whatever they are intended to kill but also beneficial organisms that make up a large part of our immune systems, mental health systems, and digestive systems. I believe that current guidance is that they only be used when necessary, as over time additionally their overuse has led to a lot of bad guys out there that have become resistant to antibiotics and have therefore become a lot more virulent. That would mean, to me, that at minimum, a diagnosis would have to be made in order to give one an antibiotic that there was in fact an infection. There are more than one way to do that. You can do a test that detects the bacteria you're trying to kill. You can also see things that indicate an infection is present, such as a diagnostic picture that indicates, say, bone loss. I have no idea in your case whether a diagnosis was made or how it was made. If none was made, meaning the docs couldn't find anything, giving you an antibiotic is a fishing expedition. Now, often a fishing expedition finds what one is looking for. Often it doesn't. But for you, that's irrelevant now. You did in fact have a choice. Docs can't force you to do anything. It's ultimately your choice, though many people either don't know that or are so scared and concerned by what's wrong that they just do what the doc tells them to do. Once you embarked upon a course of antibiotic treatment, it can be dangerous to stop it before it's completed, because that too can lead to resistant organisms. Because nobody but a good doctor doing all the tests necessary and making decisions based on proper diagnostic criteria would be able to tell you if you needed the antibiotic, nobody else can tell you definitively if you needed it or not but it may be that once you decided to start the program you now have to complete it. One way to try to minimize the harm is to take the best multi-spectrum probiotic you can find in the refrigerated section of the best health food store near you. Also, eating prebiotic foods can also help with this, such as fermented and cultured foods like sauerkraut, miso, kim chi, yogurt, and the like. These provide good food for probiotics. Killing off some of your probiotics is why the digestive problems often follow a course of antibiotics. Other problems can be recurrent infections, yeast infections, skin problems, etc. But when you do need antibiotics, they can save your life, so like everything docs do, it's always a trade-off. I don't know if that shot you got is part of a course of antibiotics, or if the course would start with the 28 day program. Nor do I know how the decision was made to do it. It might have been the doc's best guess based on what your were reporting. It might have been to get you out of the office. If might have been that many docs give pretty much everyone who comes in an antibiotic, which caused the antibiotic resistance problem in the first place. Can't say, wasn't there, have no idea how distressed you were or how irrational you might have been which can play a role in the doc believing he had to do something for your mental health. Again, wasn't there, but you've been posting a lot about doing some fairly unusual things experimenting on your body, so maybe something happened, but again, you were there, I wasn't. Asking your doc is the best you can do at this point what he found, and why he ordered what he ordered. Peace.