Jen, you are not an idiot.
You've shot lower numbers before, and you were apparently able to test, so why were you afraid to shoot? Just curious. Did you post for help?
A few thoughts, looking at your SS:
Did the vet tell you that Mr B might be experiencing the Somogyi Effect? If so, next time you talk to him/her, ask what documentation he/she has that proves it exists in cats. I think you will find out there is none. There is even question as to whether or not it happens in people.
Please refresh my lousy memory about your schedule. Are you able to test more during the day? Are you following SLGS or TR? It's really hard to see if Mr. B is overdosed or going low and bouncing without more midcycle tests. It's entirely possible that he has gone low during one or more of the past several cycles, and then bounced. With only the PS tests, all you would see is the bounce numbers. If you could get a curve, or at least get two or three midcycle tests, say at +3, +6 and +9, that would help a lot to fill in the picture.
What is your feeding schedule. Do you feed late in the cycle at all?
On 5/22 you referred to "scary numbers". What numbers were you scared of? Why did the vet tell you to reduce?
Do you have any numbers from the time he was at the vet? What number did they get that showed "borderline hypoglycemia?" A fructosamine test is more of an average than an actual BG reading. I've never heard of it showing "borderline hypoglycemia", so I'm really curious how he/she came up with that.
Larger doses have bigger depots, so when you skip a shot, it takes longer to drain and then longer to refill it. Standard is up to 6 cycles, but ECID. The same is true with bounces. Some clear bounces in one day, some in 3 or 4.
I'll stop bombarding you and let you answer my questions. Stop blaming yourself. You're doing the best you can.