If the Xanax is helping that much, you might have to start considering that maybe your sleep issues are anxiety related. Try to enlist the help of professionally trained psychologist. Sometimes lay therapists could help, but the pros can diagnose and team with psychiatrists to prescribe medication. However, depending on the severity of the issue, you might not even need meds. Cognitive behavioral therapy is usually extremely effective at dealing with anxiety, PTSD and related issues that can cause sleep deprivation. Mental health is complex and reaching for drugs out of desperation can go really really bad really fast.