Out of control

So far I have not seen anyone who has had this experience, nor can my doctor explain it. I have had this thing happen to me 3 times in my life since being diagnosed, which was 12 years ago. What happens is my blood sugar will be low, somewhere in the 70s, and I eat without taking insulin. My blood sugar will go up to 100 or so, then drop right back down to the 70s or lower which forces me to eat more. During this time I am not taking any humalog for the food I am eating, as I am trying to raise the level. The blood sugar will then go up, maybe into the 160s, then drop AGAIN right back down. This happens within minutes because at this point i pretty much go into a panic mode and am testing often. This obviously makes me eat more but it just will keep doing this for roughly 1-2 hours. Sometimes the blood sugar will go up into the 200s but then instantly drop down to a low reading again. By instant, I mean INSTANT. I have tested before at a 230 reading, then tested again 5 minutes later to find I am at 90. I want to repeat this has only happened 3 times in my entire life, but its a frightening experience as I am completely unable to control what is going on. When food isnt able to keep you from dropping, it kind of makes it scary. My attempt to understand it has led me to think that my lantus is building up and being released all at once for some reason. Note that this normally happens on a day when I dont eat a lot. I think all day I had a sandwich, a banana and a bowl of pasta. Regardless of what I ate that day though, I dont understand why blood sugar would go up and down like that with no insulin in my system. I can eat 8 units of carbs and it still will be doing this. Anyone else had an experience like this?