That's not really how DDoS attacks work? You might wanna change your Wifi password though, or if you don't want to do that unless nessecary, most ISPs provide a tool to sheck all devices that have the Wifi saved to see if that's actually what's happening

I can check who is using our internet and all the devices connected to it. None in which are using internet besides my computer. Typically my family stays off of it at night and even if they're on it in the day, it's perfectly fine.