Don't worry you're not alone! I've been fortunate in that my viewings have been steadily rising over the past few months from about 400 per day to about 700 per day (so I don't think I'm doing anything wrong). But today they've dropped back to 400 and presumably may still fall a bit further.
Hopefully as jainismus says, it is just a stats fault. Or it may be a google algorithm change. But usually these things are just a temporary blip, so hopefully within a week your figures will be back up again to normal levels.