data limits, broadcasting wifi

[srsizzy]

ok, this is a dumb question, I know it's definitely been asked somewhere, but I don't know what to search to find it.

I've been using wifi from my phone this month, and I just looked on my sprint account and found that from various things (a lot of video and image browsing) I've used 9GB of data in less than a month. This seem like quite a lot, I don't remember reading anyone using this much. I have unlimited data on a SERO plan.

should I be worried? I'm definitely going to halt the usage for now, but it seems like if any sane person looked at my phone usage they'd realize it'd be incredibly difficult to use that kind of data transfer on just the phone.