I was switched yesterday from lofepramine (a tricyclic) to Mirtazapine.. (something I've never heard of (and believe me I've tried a lot of meds ! )

I want to know about possible side effects, ones that real people have experienced rather than those listed in the PIL.

Especially, does it affect appetite/weight ?
Sleep ?
Sex drive ?
How long before an improvement (if there was one) ?
+ anything else yo think I should know ! I'm really hoping this is going to help me !