Just ask her if a set time and day for your sessions can be made and see what the two of you can come up with together. Most likely this time, with the craziness of the pandemic/online issues, she has few clients with set times, so she's trying to work around a bunch of varying schedules. But, let her know your preference for a set day and time, come up with a plan, and hopefully that will be more set for both of you.