Hi Jenni
Good name that LOL
There are a couple of things that happen to us and the first one is Carb Creep. That's to say those of us who count carbs know very well from experience exactly how many grams of carbs we have on our plates. Yet somehow after getting iffy results for a while, when we actually check it properly on the scales just to make sure, it turns out the portion has increased over the months and years and so is quite a bit larger than it was to begin with - or we read the packet and discover 'they' changed the recipe and didn't tell us.
The second one is, WE change. It doesn't have to be because of a life-changing event or anything momentous at all - it just happens anyway in the normal course of events. This is particularly noticeable to T1s using an insulin pump, because there is a lot of adjusting you can do on a pump. We start off and gradually adjust our rates of insulin delivery over the day to suit. Within a month or two we need to adjust em again. And that's repeated again and again and again. Ostensibly, absolutely nothing has changed with regard to the weather, activity, hormones, concurrent illness or food.
There's absolutely nothing we can do to prevent this in the case where we didn't do anything to cause it in the first place! If you start blaming yourself for it you are on a hiding to nothing once you've eradicated the things that probably ARE your fault.
So like when you have a virus, treat the symptoms, if your BG ain't right, just do whatever you need to do to make it right - whether it's giving up carbs, taking more exercise or taking medication.