www.healthline.com/health/eosinophil-count-absolute#results5"An abnormally low eosinophil count can be the result of intoxication from alcohol or excessive production of cortisol, like in Cushing’s disease. Cortisol is a hormone naturally produced by the body. Low eosinophil counts may also be due to the time of day. Under normal conditions, eosinophil counts are lowest in the morning and highest in the evening.
Unless alcohol abuse or Cushing’s disease is suspected, low levels of eosinophils are not usually of concern unless other white cell counts are also abnormally low. If all white cells counts are low, this can signal a problem with the bone marrow."
Did you start taking something to adjust your cortisol levels? Did you do this bloodwork at a different time of day then you normally do?