This is an old thread, however, for anyone that comes to it looking for advice, trazodone is a dose dependant multifunction drug which at daily doses below about 150-200mg acts only as a sedating antihistamine. The antidepressant response typically begins at around 200mg and the recommended adult dose range is 300-600mg. The hypnotic/sedating effect diminishes as doses increase and tends to be minor beyond 200mg, especially with the extended/slow release formulations which are better at maintaining plasma levels above the sedation threshold.

Stephen Stahl's: 'Mechanism of Action of Trazodone: a Multifunctional Drug' [PDF] is a useful guide to this underrated med.