I have done to glucose tolerance tests blood in morning 4.6 then took glucose back two hours later and blood was 2.7 .was reapeated a few months ago blood 4.8 then 2.4 .whats going on .feel my blood going low on various occasions I don't have diabetes but have strong family history ,brother and sister type one.am going to go into hospital to get a 72 hour dating .whY is this happening and is it diabetes