Data usage high

I have a secured network at my place and I haven't been home for about a week until arriving last night. I keep getting messages that I'm close to my data cap. I don't download/play games on my home wifi I'll stream every so often and maybe watch youtube. The wifi usage on the phones I have on the network equal to less then 100gb. I have a ps4 that I strictly use for streaming. Even then I'm somehow getting to over 1 to within a few days of my bill cycle.