How much time did you allow between your 2 units of Humalog and starting to eat your yogurt? I, almost always, pre-bolus for 30 minutes for breakfast. For a while I was prebolusing 60 minutes at breakfast. You could use your CGM and watch your glucose trace carefully to avoid any hypo surprises.
When you think about dosing insulin while trying to maintain good post-meal bGs, we only have two things with respect to insulin we control. Dose size and timing are the only insulin levers we can use. I think pre-bolusing is under-appreciated by the average insulin-using person with diabetes.
When was the last time you adjusted your insulin to carb ratio? Do you have different I:C ratios at different times of day? I use a more aggressive I:C ratio in the morning than later in the day.
And our docs, in general, are so hypo-phobic, don’t encourage more than a “token” pre-bolus time of 10 or 15 minutes. That might work in some situations but to use it like it’s some sacred rule is a mistake. Ponder’s “waiting for the CGM bend” is a brilliant tactic.
I think injecting insulin into muscle is a great technique to hasten insulin action. Congrats on your walking habit. It’s normally a super tactic to bring down high BGs.