What you are experiencing is very common, and called a "false hypo", and you get them because your body isn't used to having normal blood sugars. They are a kind of "withdrawal" symptom. You get used to it after a while and the symptoms fade (although I still get a mild headache if I drop much below 5.5 mmol/l).
If you are a Type2 on Metformin and diet, then the chances of you getting a real hypo are very slim (although not impossible)*.
My advice is (while your BG is above 4 mmol/l) to grit your teeth and bear it, while congratulating yourself on your good control.
*(If you are on insulin or any insulin production stimulating drug then you need to be very aware of the risk of real hypos).