first welcome to SR
stick around there are alot of people here who can offer advice and support
what stood out to me in your post was.........she pops ambien like chicklets
my thought is that you may not be looking at street drug addiction but rather prescription drug addiction
does she have different doctors whos refilling the ambien etc
also you said........how do I confront her.............well the thing is addicts while active will lie to protect their addiction so asking her will probably do no good.............
I am not sure what advice to offer, except read the stickys and stay around reading all you can about addiction and others will be around soon for more help!