hello Ashley,
so I am not a doctor, so you might want to try this question with a cde or endo, now that’s out of the way.
typically your body stops making insulin completely 3 mo to 3 years after diagnosis it can be very long and everybody is different. if you had really slow onset, maybe you were making a lot of your own insulin this whole time, if you were then your bs control could have been awesome and easy until now (and when you said that, it is what sparked my thought).
the general rule out of the “Think Like a Pancreas” book is: you have taken enough short acting insulin if your bs is no higher than 50 mg/dl at 2 hours than it was when you started to eat. so if you started at 150, then at +2 hours you got a 200, that means your fast acting was enough. This works pretty good for apidra or any lispro, does not work for “regular”. you can just keep increasing fast acting ratios until it works (only if you are totally comfortable, because it can be dangerous). the book by the way, is an excellent read in my opinion.
so yeah you can also have changes in sensitivity from stress, caffeine, irritations and inflammation, changes in sleep, jobs, housing, taxes, if you are also taking any kind of steroid, pregnancy, issues and problems with your adrenal gland, etc.
you could also take a look at the kind of carbs. for me, rice, potato, white bread and cereal raise my blood sugar faster than my humalog can bring it down. so when I know what I am eating, I take my insulin 15 minutes before I eat any of those. pasta, pizza, Chinese food, ice cream, my sugar rises slower than the humalog so I use a special recipe for those foods (I pump and it’s called a “square wave” bolus on mine). for more information check carb types for “glycemic index”
you wouldn’t want to change lantus injections, unless your bs is rising or falling when you are not eating. that basal insulin won’t help your post meal numbers at all.
I get rammy sometimes so if it’s cereal (for example) it is good to actually measure serving sizes. I tend to unconsciously increase how much I pour out over time so the scale doesn’t lie.
cheers no worries, everybody’s sensitivity is different. it also changes as you get older. I had a 1:8 in the morning and 1:12 in the evening. I changed my exercise habits and now it changed to 1:10 mornings and evenings. go figure. this is part science and part luck: so good luck!