If the hearing loss is recent, it could be a viral infection or the first sign endolymphatic hydrops; you could consult with your ENT for the appropriate medication- usually a nerve regenerator and ginseng extract are given, with or without steroid in the first case, or an antivertigo drug in the second case. An MRI or CT scan may be required to make sure there is no tumor like an acoustic neuroma or a glomus tumor. Try sleeping with a ticking clock or watch by your side; it helps to distract from the noise. Long courses of drug therapy, hearing device, behavioral therapy and surgery ( to destroy the offending nerve and sensory organ) are the options when simpler measures have failed and no cause is found.