This doesn't sound right. You got a stomach ache, and that precipitated an anxiety attack? Is that common for you, that very small things cause you to have anxiety attacks, or was this the first time you got one? I'm asking because being put on an antidepressant for one anxiety attack is pretty bad medicine. These meds are used for chronic problems that are badly affecting your life and are resistant to other forms of treatment. For a first problem, usually you would be sent to therapy. But if your gyno thought you had a hormonal problem, why the antidepressant? They don't treat hormonal imbalances. Now, I'm not sure that taking the hormone is all that great an idea either, there are also less dangerous options to start with, and when those don't work you work your way up the ladder of risk to deal with a problem. But that's a different question. As for your response, it is a common side effect of Prozac for it to cause anxiety, as it's a more stimulating antidepressant for many people. Sometimes that goes away, sometimes it doesn't. Only time will tell. But taking sexual hormones can also cause this side effect. Can't really tell you what to do, you're seeing doctors, I'm just raising questions so you might think this through more. Your family doctor is not an expert on mental illness or the drugs used to treat it, a psychiatrist is the medication expert, though that's not to say any kind of doctor is that great at separating fact from pharmaceutical company marketing, and a psychologist is the expert on, well, psychology if you want therapy. A lot of physiological things can cause anxiety, and sexual hormone imbalances are one of them. There are many others. The question you haven't addressed here is, as I said at first, is this something that happens to you regularly or was this the first time? That has a lot to do with what you do about it.
So, they must feel you have a reason to need an antidepressant. When in the ER, you must have presented as though you need a chronic medication to help you. But I'd want to follow up with your family doctor to discuss this. In general, taking something like Prozac will sometimes have some start up side effects. They vary form person to person. You are on a really low dose and that's a good start. Keep taking it unless it is unbearable but you need to have a doctor guide you. Have you called your regular doctor yet?