I was prescribed Diazepam in 1994 (ish) and, like the OP I was having a really bad time with anxiety, about 18months later. I found them and took one (as you do) and woke up in hospital with a tube coming out my mouth.
Not good.
They were in one of those little brown bottles, not in a strip so that may have made a difference and I had lost a lot of weight so my physical make-up had changed.