Welcome Galtar,
eating well during the day, and any bit of exercise can help the body ease into sleep as its temperature is able to drop lower after a peak. Seems there is a difference in how the routine influences sleep. My second one can be long and I do it sometimes late night right before jumping into bed, and if anything I am much more calm and relaxed, unlike when concentrating at something all day which really throws me off into light sleep.
Have you done other forms of meditation before AYP? If not, try giving it some time and see if your body is able to compensate or adjust.