You went from one benzodiazapine to another, it should not really matter to those receptor which one is filling them.
Hello. Im not a doctor but 20mgs of diazepam is not equivalent to 3mgs of xanax. According to the Ashton Manual (the gold standard with regards to benzo detox) 3mgs of xanax is equal (approx) to 60mgs of diazepam. The ratio for alprazolam to diazepam conversion is 1:20 or 20mgs of diazepam for every milligram of xanax (alprazolam).
http://www.benzodocs.com/converter.php?
I suggest you stay extra vigilant and self aware. If you feel like you are withdrawing, contact your doctor immediately. When transitioning onto diazepam the primary goal is stabilisation not detox. Only when you are stable is it then possible to begin detoxing.