Mobile Hotspot Data Seemingly Disappearing

For the past several months, I've had issues with my mobile hotspot data seemingly disappearing. I have a Mobile Elite Plan and get 40GB of mobile hotspot data a month. The only device that I connect to this hotspot with is a Windows 10 laptop. The first month that this happened, I didn't think much of it. I thought maybe I had some downloads that would automatically start on my laptop. I went through several settings to ensure no downloads would run without me initiating them first. I also enabled data tracking to see where my data usage was going. My data has continued to disappear. I checked my month's usage today, and the total didn't even amount to 10 GB of my 40 GB limit. I notice this drain the most towards the end of my billing cycle. For example, I connected to my hotspot with my laptop this afternoon, and the remaining 6 GB of hotspot data that was apparently left disappeared within minutes. All apps were disabled at startup, and no downloads were initiated. Is there a reason why this is happening? I rely on my hotspot as I live in a rural area. I feel as though I should be able to rely on my hotspot when I need it, especially when I'm paying for the highest tier of service that AT&T provides.