Clare,
I don't know much about about Schizoaffective Disorder. So I did a mini research and I found out a little bit more. From what you describe of your situation, you seem to have more of the depressive symptoms. (Also, it said that Schizoaffective Disorder and Bipolar Disorder are so similar it is hard to distinguish between them)
Here are some of the drugs they suggested as a source of treatment:
Mood stabilizers and anti-psychotics such the following - Depakote, Lithium, Carbamazepine, Resperadal, Seroquel, Abilify and more...
Also it is stated that selective serotonin reuptake inhibitors (SSRIs) are greatly preferred over the other classes of antidepressants as a treatment for the depressive type of the disorder.
From what I have read leaden paralysis is a possibility in the disorder, it can also be other things. So I would deffinetly have all your symptoms and all your medicines checked out by your doctor. I am not a professional and do not want to give the wrong information.
I hope you find the info that you are looking for.