I would say it's fine. I don't know too much about medication, but weed I don't think would have any affect on them. Might make you feel a little more funny, diazepam is that for depression or what? Pink pills? I think my ex boyfriend was on those.

Anyway..I am no professional or anything, but weed generally tends to be fine with most things.
However if you feel that you might not be able to handle it, then don't do it. All depends on how you feel.