Drugs

What the devil is it having a pain killer that if you stop taking it all at once and not just cut back a bit till you are not taking it anymore, you bloody well end up having trouble sleeping.
What’s worse is when you are taking said pain killer, and it loses it’s effectiveness so you take more, but then you stop so your body will clear it out so THEN you end up not sleeping well. Damn drugs and their odd ass side effects.