Hotspot Blue Band at top of iphone displays 2 connections

Recently after connecting laptop to iphone4, I am noticing that the blue band at the top of iphone screen displays: personal hotspot: 1 connection. Then after 5 minutes, it will display: personal hotspot: 2 connections. When using hotspot with laptop, I am utilizing yahoo mail, or idoling my facebook profile page and checking it once in awhile....basically, I shouldn't drain 1GB in just 3 hours, by looking at my profile on fb, and sending a few emails on yahoo I'm not using or viewing videos, media, music, nothing...Verizon seems to think what I'm accessing on my laptop IS using that much data! My thought is that other people are accessing my hotspot or wi-fi and that may explain why my usage is being sucked like crazy and the blue band displays: 2 connections! Can someone enlighten me on their thoughts, or how to disable other users from getting free internet off me!! Because this is a struggle:(