Got to be quick, but remember this, it's important:
The brain receptors can be quite 'malleable' - this is known as neuroplasticity. In times of danger (or stress) the brain is able to detect minute details that it might not otherwise be bothered about. Once 'tuned' into these details it's difficult to 'detune' it. In the case of tinnitus, this 'detuning' is known as TRT (Google it). View your auditory mechanism as a UHF radio - as well as what you want to pick up, it's capable of detecting a load of cr*p as well.
Advice here is no substitute for a good ENT / Otoneurologist, but until you get to one, try to relax and 'detune' the tinnitus. Don't be scared of it - the chances are that it's nothing to do with your physical health at all. Also remember that tinnitus does not always suggest hearing damage, as the stereotype suggests.