Are you on insulin treatment? External insulin will create hypos during excercise if regular fueling is not followed. It sounds to me like a hypoglycemia attack, although they seem to be rare in type 2's who are not on insulin. High effort will increase your insulin sensitivity radically so if you have abundance of insulin production then a hypo is a very real possibility.
The nasty thing about excercise induced hypoglycemias is that you might not notice them before it's way too late. Normally a person will notice the symptoms at 4mol (it's what we use in europe. Look up conversions. I'm on my cellphone so it's too much of a hassle). At 3mol the symptoms are really bad and at 2mol you will feel like sitting down or going to sleep is a really good idea. Under two normally means unconciousness. But when excersizing i've gone as low as 2.4 without noticing anything until it hit me like a sledgehammer to the face. So i need some other markers which by now are pretty surefire.
When riding a bike when my lower back starts to ache it's time to eat lots fast. Lower back pain usually happens in the 3-4 region. For reference 5 is normal and 7 is highish.
So try to measure more often and find the ques and hints your body gives you before you bonk.
I'm a type 1 if anyone is wondering so external insulin for life. Not so bad when you know how to use it. Mad muscle growth bro