I have the same problem. I am taking a natural antidepressant called Picamilon. It doesn't work as well when I have the flu or a cold, but I think I am better than when I was not taking it. What kind of antidepressant are you using and is it working for you the rest of the time? I would like you to write to me and keep in touch. If one of us finds out more what this is, we can let the other one know. Thanks.