Do you get any S&S when you don't get enough sleep? I find I get a rapid heartbeat.
Also, I get irritable, nauseated, and my blood sugar goes haywire. Then, I reach a point where I can't sleep even if I want to and have the opportunity.
Ah, the joys of shift work.
An observation: Naps are not cumulative. You need at least 5 or 6 hours of interrupted sleep for it to really help.