Question: Just wondering if everything is normal on my cell phone... It's an LG and they stopped updating, but I don't remember this behavior before...

Answer: 
You could, potentially, manage your traffic by following a couple of rules:

1. When you are on the move, i.e. using mobile data
a. Turn **OFF** Wi-Fi
b. Turn **OFF** VPN
c. **Enable** Mobile Data
2. When you are expecting to use an unsecured WiFi *(e.g. Internet Café, Airport)*
a. **DISABLE** Mobile Data
b. Turn **ON** VPN
c. Turn **ON** Wi-Fi

The order that these are done in is important. This does, *of course*, assume that you do trust your carriers internet access to be *reasonably* private.

You could potentially automate with something like If This Then That or you may be able to find an app that lets you have a button to toggle these settings.
There is an issue here that NordVPN do not recognise. From Jan - Oct this year I had adequate mobile data. In November my mobile data consumption rocketed up. In December the NordVPN app consumed most of my mobile data allowance, so I turned mobile data off. I contacted NordVPN, they have not got a clue. To me something in the App is consuming data and this error has emerged in Q4. I'm going to get myself another VPN that pays a bit more attention to it's customer. I would recommend that you do the same.

When I look at the mobile data usage log for Nov and Dec, NordVPN is the number one mobile data consumer.