I hope that when you feel this way you do an immediate glucose test to see what your glucose level is at the time. I would also strongly suggest that you wait 15 minutes to a haf hour if the glucose number is NOT hypoglycemic and test again. I am not a physician, but am a long-time type 1 (35 years on insulin). What you are feeling MAY be the actual dropping of your glucose numbers even if they are not below normal when you first test. Many diabetics can feel when their glucose levels are dropping fast. I am one of these, and I have learned that my feelings are ALWAYS correct, even if the glucometer shows me to have a healthy glucose number at the time. If I do a second test in a half hour, I will always see that the number dropped considerably and what I was feeling was the dropping gluocse. So for me, personally, I treat this sensation with juice or other carbs and then test again. I have heard from other diabetics who can sense the drop also.
As for the symptoms being different from the norm, I think you will find as years go by that there are MANY different types of symptoms of hypoglycemia. Sometimes you can get dizzy, at other times you simply get sleepy, and sometimes you think clearly but are unable to command your muscles properly. Although the symptoms are different (different parts of the brain control different life functions and it sort of seems that different parts of the brain are having difficulty at different times), all point to hypoglycemia. Don't guess about it -- do an immediate finger ***** and if normal and the symptoms are continueing, do another one 15 minutes to one half hour later, with coke or juice handy. The panicky feeling is also a symptom of hypoglycemia, and sometimes depression hits hard with hypoglcyemia. The quick drop may well be your problem.
If you are experiencing increased heartbeat when this happens, you may also want to ask your doctor to check your thyroid levels, for many type 1 diabetics have thyroid abnormalities at some time in their lives. The same immune system problem that causes the body to attack the insulin-producing cells can also cause it to attack the thyroid and produce odd symptoms such as heart palpitations. You also may have low blood pressure. I would do the glucose checks and treat with juice if necessary, but also talk about this to your doctor if it keeps happening, for it may be a symptom of some other problem that can be easily fixed once diagnosed. I wish you the best.
As you probably know, we're not physicians here, but there's lots of real world experience here among the folks who post. I have had "fleeting" episodes like you describe, but they don't last more than a few seconds.
My advice is to begin to record all the details around the times of those episodes. Time of day, day of week, location (home, school, work, "out"), blood sugar and all the physical symptoms you feel. Also note what you do to feel better & how long it takes to do so. Finally, note your stress level when the symptoms happend. I understand you would feel a bit panicky once it starts, but try to note how you felt before it all started. There might be environmental triggers to your emotions that begin a chain of events.
Some insulins have shorter/longer peaks and duration. Do you notice any patterns related to the time interval between when you take a shot and when you have these episodes?
Your a1c is pretty good, so your overall management seems good. GOOD FOR YOU!! Another avenue to consider is your blood pressure and/or potential side effects from other medications you take. Those symptoms can be caused by many factors, including low blood sugar.
Talk with your diabetes specialist about these other ideas if they seem like they might help explain what you're experiencing. Tune in again, because I'm sure you'll hear from others.