Your body might have gotten so used to taking those sleeping pills which could be why they're not working anymore.
You might check with a doctor about some stronger sleeping pills. Doctors can prescribe some stronger sleeping medications than the over the counter ones.
Here are few other things you might try.
Avoid Coffee or any other things with caffeine a few hours before bedtime. Caffeine keeps us awake.
Avoid TV or computers an hour before bed. Shut your computer TV or other electronics down an hour before going to bed.
Also try drinking a warm glass of milk before bed. This works for some people.
Good luck. I hope you're able to get some sleep soon.