I'm currently on antidepressants for PND. They've minimised the depressive symptoms and I am much happier while I am taking them. I still have bad days occasionally, but they are no where near as frequent as they were. I haven't found it to impact negatively on my happiness.
I have found that my anxiety hasn't been managed by the antidepressants as well as the depressive symptoms. But, apparently a side effect of some antidepressants can be anxiety for *some* people. I've found that management techniques have helped most with this, but they're hard to use when you're close to flipping your lid.
If your psychologist feels that medication may be warranted, they might write to or call your GP. However, as other PPs have said, they don't do the medical training to make decisions about medications.