How to interpret Lactate Threshold non-detection?

So I tried to do it, the lactate threshold test.

Fenix made me run through several heart rate zones.
My top HR measured this year is 189.
I could keep up all the way up to 170-180 zone.
Then in 180+ I could hardly sustain the required tempo for 100 m.

And so I cancelled the test and continued normal running.

Now how to interpret this?

Does my lactate threshold lay above another threshold, let's call it 'my poor form', which prevents me to reach the first one?
From what I'v read about LT, it should be accompanied with the feeling that my muscles can no longer sustain the effort.
But before this happens I have the feeling that my lungs can't keep up.

I'm not in my best shape indeed, I returned to intensive training some month ago after a rather lousy year.

So, any insight?

Thanks.