Everyones body is different and it depends on how much anxiety there is. Under extreme cases I've not been able to fall asleep at all without some type of pill to help me out for days on end. I think the stresses created in the modern world are nowhere near what nature intended for us.
If you keep having constant sleeping issues I don't think its is very good to take sleeping pills as a solution. Perhaps you sshould try an antidepressant? In 3-4 months they can help you and solve sleeping solutions. (ADs help relieve stress in the brain) . I have been taking Valdoxan for almost a year now due to my generalized anxiety and this is what has helpd me sleep and also deal with the stress. Without I probably would be like you.
Or if you don't want to take ADs try to change your lifestyle/mentality that is causing stress.
However, of course everyone is different and its better to take pill than stay awake for days. But I do believe that frequent pill taking is only ok if one has tried to deal with what is actually causing the problems.