Yes, my experience of human insulin was similar. I had no warning symptoms when my BS dropped at all. My worst experience was on a Friday evening. I watched a film till 11:30pm and then got up to switch off the TV and head for bed. I had had hot chocolate and digestive biscuits about half an hour earlier during a commercial break, but was waiting till I actually got to bed before my evening basal injection. When I put off the TV, I discovered that my legs would not support me and dropped to the floor feeling shaky. I crawled to an armchair, but was unable to pull myself up. My mind was perfectly clear and I immediately decided that my sugar level had to be responible for what was happening to me. I could not reach my handbag with my glucose in it, or my coat hanging up in the hall with glucose in the pocket, so had to crawl into the kitchen for the Lucozade. I could not reach a glass or cup, so had to drink it out of the bottle, supporting myself with one hand. By now, I was totally exhausted and lay on the cold kitchen floor for about ten minutes before slowly crawling back to the sitting room, pushing the bottle of Lucozade ahead of me because I needed both hands to crawl, but was afraid to leave it behind. Once back on the warm carpet I fell asleep or lost consciousness, unsure which. After about an hour and a half, I woke up, feeling dreadful, aching all over, with a thumping headache. My meter showed 6.1 mml - and I had drunk at least half a large bottle of original Lucozade.
I reverted back to animal insulin as soon as this was possible. Until then, to stay alive I had to keep my BS above 6 at all costs. On later occasions, my legs would suddenly give way when I was crossing the road and I was lucky to make it to the pavement. It was all a nightmare I will NEVER EVER forget.