As someone who does all the scheduling at a T office, pretty much this. I was out sick for 2 days recently, so couldn't respond to any emails and no one else has access to the email but me.

Also, my usual turn around time is within 24 business hours. My own T has a 48 hour response time (except over weekends/vacations). If I know the answer right away, I respond as soon as I see a message. If I need to check a T's availability or office availability, etc., I wait until I have all the information to respond- sometimes this requires waiting on not just the T but also other clients to tell me something first (cancellations, rescheduling, special events ,etc). If someone cancels, I just take that at face value, because I don't have time to convince people to come in.

Also, not often, but sometimes things do get buried in my email, so if you don't hear back after a couple of days, then politely follow-up. When people call and 5 minutes later email me and then call again within 10 min/an hour/whatever, it gets to be a bit much. I sometimes have some other task to do that requires more urgent attention, but will get to an email when I can.

BAsically, there are many reasons you may not have heard back yet, and I know it's hard waiting, but try to be patient. It's still within a reasonable time frame for them to respond. Are there some coping skills you can use while you wait?