Personally, I don't get hung up on the "4 is the floor" saying, as I regularly run at under 4, and am absolutely fine. Currently, my 7, 14, 30 and 90 day average of my finger prick bloods is 4.2. My HbA1c is a bit higher, so I obviously miss quite a few peaks, but at present, I'm not stressing over that.
It is possible to hypo on Metformin. Indeed, it is possible for perfectly "normal", non-diabetic people to hypo.
Where do your bloods normally run, and have they been generally dropping lately? If your scores have been coming down of late, it is possible that is the reason you've felt a bit odd and caught the under 4 score.
As I say, I'm fine until I get to 3.4, which doesn't happen very often, but at that score, I feel a bit empty. I certainly don't grab a bunch of jelly babies or any of the other classic hypo treatments, because my view is, that would just set me on yo-yo, where I would shoot up (I have no idea how high), then come down again, and in all likelihood feel rough on the down again. If you read about T1s treating and over treating hypos there is quite a bit written about these rebound effects. If food is not imminent when I feel a bit off, I just have a cup or tea, with milk, which just lifts me gently into a much more comfortable score, then I eat as I normally would. To be honest, I don't think I've even bothered to test after the tea because if I feel fine again, that's good enough for me.
Other people have differing views, but that's my personal experience and view. I'm not saying it's how you have to be.
