See a doctor and make sure you get all possible tests done. If you haven't heard loud music, it might be something else that CAN be cured. The thing I advise concurrently is to learn to manage your fear. Calm down and don't think about stuff that hasn't happened yet. I tell myself :' calm down, it's just some frigging noise. I am not having a heart attack or something life threatening.'
Remember, things can get better, there's no law that says that they must become bad. Also, as advised in an excellent article by ATA, do your own research too. Don't limit yourself to just accept the doctor's opinion. Read about tinnitus but only set a limited amount of time for it. Get the free leaflet advice from all the major tinnitus associations, they are very helpful, for example if you can't sleep after 30 minutes, get up and try later.
Also mask the noise with a 'masker' : I use constantly an mp3 player with the sound of falling rain (without thunder). I also leave stuff on, like a fan, tap water, anything that creates pleasant or 'normal' noise.
Stay calm, take action, ask questions and seek help from the doctors, and let us know how it's going.
Best wishes,
WL