Why does controlled release not release??

I'm not sureI understand this .... I take Metformin XR and I watch my glucose levels sorta go up and down with that.
But it is controlled release ... so ... wtf?
Anyway -- test more, eat more frequently, exercise more ... all on the "to-do" list.
In the meantime the thirst is getting better.
The neuropathic pain -- good days and bad.  For one thing is s not BAD pain ... it is uncomfortable to the the point where, at its worst, it will wake me up.  It is in my feet.
The more troublesome symptom that the doc did not really explain is numbness in the hands that is related to posture.  I notice when I am playing guitar that my left hand starts to tingle and get a bit numb.  I am rather sensitive to this as a guitar player and it is, in general not too bad.  But it is incentive to follow doctor's orders closely!