What was happening to me?

All medications have side effects ranging from mild to serious. You obviously can't tolerate the medication that you were taking and it's a good thing that you don't take it anymore. If you had needed anti depressants, then your doctor would have tried you on a different one. It's really good that you don't need such medications, so feel proud of yourself to have moved on. Don't worry about what happened in the past, but do be careful if you take any medications in the future regarding reactions you might get. For example, I can't take the very ordinary and "safe" Neurophen as I am quite allergic to it and become covered in hives. A friend of mine has hallucinations like yours if she takes a certain sleeping tablet - so she doesn't take it!