As a general rule, individuals who take hypnosedatives (this is the technical name for sleeping pills) for more than 45 days will develop some sort of physiologic and psychologic dependence and will show symptoms after withdrawal.
Thus, after taking sleeping pills for more than two months you should expect to see their sleeping power diminish week after week and should also expect to have problems to quit them.
Now that you can see this effect in action, you should understand that taking sleeping pills for such a long time has been a bad therapeutic choice, and after all, it never cured the cause of your problem.
I'd suggest that you'd better see a neurology consultant and ask for an alternative sleeping medication while you try to find a different therapy method to deal with your insomnia.
Examples of common medicines of this kind:
Diazepam, Oxyzepam, Valium, Xanax, Sobril