Has anyone else been "desensitized"

I've been diabetic for almost 30 years and could always tell reasonably well what my blood sugar was doing by what my body was telling me. It seems that for the past 2-3 years now, though, that isn't the case. I'll wake up in the mornings just feeling awful and thinking my blood sugar is around 300. I'll check it and it's in the low 100's. I've actually had it plummet twice on me while driving. In both instances of the drops, I didn't have any of the tell-tale signs and it completely caught me off guard— very scary. I was wondering if anyone else has had this desensitization happen to them.