Hi there, when I was first diagnosed, like you they put me on 'fixed' amounts of insulin per meal based on what my 'usual' diet was. I think this is standard procedure as what they are doing is trying to work out your carb to insulin ratio and they can only do this by trial and error at first. The problem with that is that it is little more than a guess and as the weeks go on, YOU will discover for yourself how many units of insulin you need for each 10g of carbs (easier to work out that way).
In the meantime, you find yourself going low, as I did all the time, so you follow the hypo rules and eat a couple of glucose tablets immediately followed by 'long lasting' carbs. Your glucose tablets & bread or biscuits is probably around 30 carbs or more....so a reading of 3.5 (which is at the higher end of hypo if you like) takes you up to 11 or 12. Outside of hypo land, you would normally take insulin to cover 30g of carbs.
I know it is very confusing but in a month or so (maybe more, maybe less) you WILL settle into a routine that is right for you and this will be worked out by your own readings, your own patterns, your own experiments (including those based around what happens when you exercise or go to work or go to the shops, etc) and the help from your Diabetes team which is very important. You must contact them regularly as based on your reports back and readings, they will adjust your units to accommodate it. For example, if I go lower than 4 now, say at 3.5 I would have a glucose tablet (dependent upon whether my next meal was due) but I wouldn't follow it up with bread or a biscuit because I know that would take me far too high. If I was below 3 then yes, I might well have a biscuit or something under 15 carbs because I know I don't need to inject for that.
Once you are confident and more experienced you will be doing this yourself but in the early days you do need their help as insulin and its actions are not easy to combat. I never went out for about a month after diagnosis, I was afraid of falling to the floor, afraid of what might happen if I went hypo. Looking back now, I feel a bit foolish because I now know that yes, that might happen but chances are it won't because I am more experienced at knowing my body.
Of course, none of us can say do this do that because you have to get advice on medication & insulin from your team, but DO phone and speak to them, they can explain things to you and work out any adjustments to your doses. x
