Discouraged after AnT Test

I live at 8500′ in Colorado and usually train at similar elevations. I started running consistently in May, and started the marathon training plan a couple months ago. I have been frustrated because I don’t feel like I’m getting faster/better. My AeT is 144 (typically this is about an 10:00-11:00 mile depending on the terrain). I did the 30 min AnT test the other day and guessed my AnT would be near to 152, but I could not sustain 152 at all. 150 was what came back as my average (which is like 4%) – and even at that the test was HARD. I really struggled. I did it on a graduation incline trail, and my pace was 11:15 which feels dreadful for going as hard as I was (though it was uphill). I’ve been feeling confused since about what this means. The notes say I should train now at Z1, but Z1 for me is essentially walking. Do I need more time building my base? I’m feeling discouraged.

A few notes which may, or may not be, relevant:

– I have had many botched training days because of the smoke levels outside, I feel like my running performance since the smoke came in over the summer has gotten worse, even on the clear days.

– I do have asthma, though it feels well controlled? I do still feel like my respiratory effort is high compared to my heart rate sometimes, especially when I head any higher above 9,000′. Sometimes I feel limited by feeling out of breath, though my body and heart feel fine – is this common, or could it be a result of my asthma?

– There are no flat trails around here. My flattest runs average about 400’gain over 3 miles. I am walking most uphills still to keep my HR below AeT, which does affect my pace and slows me down. Should I still be seeing the pace improvements that those on truly flat runs will see?

– I did do a run at 3000′ elevation a few weeks ago and felt like a superhero. Lungs felt fantastic down there!