I have no medical qualifications whatsoever, therefore you can treat the following with as much disdain as you like. Or you can take it seriously.
If you are taking benzodiazepine drugs (diazepam alias "Valium," nitrazepam, temazepam etc.) then be warned that, in order to maintain a similar level of effectiveness, you need to increase the dose over time.
It is also well known that it is very easy to become dependent on these drugs and stopping them can be very, very hard.
So IF you are taking one of them (and you don't say that you are, so the above may be useless and irrelevant) you really do need to speak to a qualified medical professional about it.