I personally consider "sober" to be from alcohol and "clean" to be from drugs.
I smoke pot like 3 times a year at when I visit a couple of old friends and probably will continue to. As long as I'm not drinking, I still consider myself sober.
I am having really bad back pain right now and I will probably be prescribed rx pain meds which I don't even like taking (not my thang). Will consider myself sober then too.
Anyway, I wouldn't get too hung up on the wording and do what makes you a healthier, more balanced person.