Anyone ever just feel so sad and hopeless

I'm transitioning meds right now; I finally got a new psychiatrist who seems to know what he's doing and actually listens to me. So hopefully things will start to look up soon. For right now though everything is still really scary, I always have physical symptoms and sometimes I just get so sad and drained. I feel so tired but I can't really sleep. Anyone else get like this? Also has anyone else had luck with prozac for anxiety?