It's going to devices around your home. You can use the system control center to see what's connected, and keep in mind that the data you get must be shared between all those things that are connected. If you do data intensive activities (such as streaming) that can eat a lot of data very fast. There are also things like smart TVs that, when connected to the internet, eat up data like there's no tomorrow. This can happen with internet connected cameras and other devices too, like Alexa and others.
To see what's using data, you can install the free Glasswire app on your Windows computers, and I think there's an Android app too. It shows you what's using data and how much on each device it's insalled.
If you don't have it already, you should also download the free HughesNet usage meter. It can help you check your data levels whenever you want, though it won't tell you where data went.
You can also buy a router that monitors usage for the entire network. @GabeU is familiar with brands and can probably recommend something.
As soon as my usage resets 2 days later it’s saying I have 0 usage left. I would like to know where it’s going, so my question is how do I find out who is using my internet or who is using all my data?
In addition to what maratsade said, many devices have their own method of monitoring the data they use. Nearly all smart phones do, and there are applications that you can use for those phones and other devices that can monitor their usage, as well. They're usually operating system specific, as in Android or iOS.
Also, just in case it may help, you can see what is currently connected to your HughesNet modem, and what was connected, but is no longer, on this modem page. The information is only since the last time the modem was plugged in, as the log clears when the modem loses power. Sometimes people forget certain devices that they have connected, so this information can be helpful.
Three of the most common data "eaters" are cloud connections, game console downloads and satellite TV receivers. The satellite TV receivers is especially the case with DirecTV receivers, as they can chew through data for various system updates, even when nothing is ever watched On Demand. Because of this, HughesNet recommends against connected them to their service.
As for routers that can monitor your data usage by device, I can't recommend any specific models, but some of the more expensive Nighthawk models can do this, and some ASUS routers have this ability when using the Asuswrt-Merlin firmware. This site is concerning the latter.