Personally I wouldn't recommend eating something sugary as that is just going to push your levels back up and your body will not get used to the normal range. A very small amount of something sweet can really push your levels back up and will defeat the object of a low carb diet. 1 jelly baby will raise my levels about 1.5mmols. Ideally you want your levels to be within the 4-7mmol range so if you do follow the advice given I would suggest no more than 1 JB but better to chose something slower release like a chunk of cheese or some cooked meat or a boiled egg, because you want your body to get used to those levels, not push them back up and then sit down until you feel better.
If you were using insulin or oral meds like Gliclazide which increases your insulin production and could potentially drop you dangerously low, then obviously you would need something sugary if you dropped below 4 but Metformin cannot do this.
Are you on Blood Pressure meds? If so, it may be that your reduced BG levels are impacting your BP particularly if you are following a low carb way of eating, and you test your BP when you feel like that and perhaps discuss reducing the dose if it is going a bit low.
As
@harbottle says, Metformin isn't capable of achieving such an impressive reduction in BG (so congrats on that). Following a low carb way of eating certainly can, but if you haven't been eating low carb, then something else may be at play..... unless you have taken up marathon running. Following a low carb way of eating is significantly more powerful than almost all diabetes medication, so that reduction is likely down to your hard work rather than the medication... Take a bow!
