You'll have to check your data usage on your phone to see what's using your data but yes it's likely video streaming got you to 100% usage. If you're still using data without having accepted going over your data, you're likely doing it on WiFi instead of cellular data.

Okay so I usually look at videos at home and my server is wi-fi. So that means I’m using my wi-fi server’s data not Koodo’s? So my data usage is being used up when I’m not at home. I live in Canada on Vancouver Island and the southern tip of the Island dips into US waters so at certain places, we have to be careful of US roaming charges. I never use my phone there but I don’t turn it off. Maybe that’s the problem?

That's right it should.
Some phones have a function enabled that if your WiFi signal is weak, it'll automatically switch to cellular to maintain a good connection.

As for the roaming charges, you can go into network settings for your phone. It's set to automatic by default. If you switch to manual, give it a minute for the list to populate, then select Koodo, it will not connect to any other network. Then you won't have to worry about that.

Have you checked your phones data usage in settings to see what's using data when?

I did check my settings and found that background data was running on a few apps which I think should be off, so I did that. I will change that roaming setting. Thx so much for the info Mobile Master