Sometimes it can still be very frustrating though because I can respond two totally different ways to the exact same foods/stressors. It makes it difficult to track everything down and get ahead but I’m trying!
That sounds like me when I started out. No matter how careful I was about weighing the food for carb counting or increasing basal temporarily for stress or exercise, my BG would go wherever it wanted to instead of where I thought I had sent it.
I solved it with two ideas. The first is the absolute basic advice from my CDE, who told me “If your blood glucose is too high, you need more insulin.” That sounds simplistic, and it glosses over all the details of basal and bolus, but many times I find myself going back to this as a way to cut through the confusion, so that I know what to do. If my BG is too high, I take more insulin to bring it down. Two notes here: I always have a tube of glucose tablets with me so that if I take too much insulin I can rescue myself. Because I have CGM and glucose on hand I don’t have to avoid “insulin stacking:” if my BG is too high I take a bit more insulin maybe as often as every half hour, then I watch what my BG is doing with the CGM. As the others said, if you get MiaoMiao to turn your Libre into a CGM that will help you stay safe, because it will notice and alert you when your BG is going out of range, even if you are asleep or distracted.
The second and most important idea that really helped me solve the problem was “sugar surfing.” I don’t try to predict everything up front to take the perfect insulin dose, because that’s just too hard. My body isn’t totally predictable. Instead, I take a reasonable insulin dose based on carb counting and what I know about stress or exercise or illness, and then I watch the CGM (or Libre graph) to see what happens. Is the BG still rising too fast or too far? Then I take some more insulin, because the graph shows that I need it. Is my BG falling when it should be rising or leveling off? Than I take some glucose to catch the fall before it becomes a hypo. The sugar surfing idea is to watch the CGM graph frequently, and make frequent small corrections with insulin or glucose to steer the BG in a good direction. One source of good instruction in this technique is from Dr. Stephen Ponder. He has a book called Sugar Surfing that gives lots of training in how to do it. (He also has a web site https://www.sugarsurfing.com/) The book gives many example CGM graphs with his explanations of what he sees in the graph and what he does as a result of that. This whole approach changes the game from “take insulin and hope that I did it right (but often I didn’t)” to “just keep making small adjustments with insulin and glucose to steer the BG in a good direction.” This way of dealing with it is comforting and effective.