Storage keeps rising and total available is not displaying correctly

The available storage on my main site is displaying in the dashboard at 100 MB despite the fact that I have it set to 1000 MB at the moment... and the amount of storage used has gone up 200 MB in the past 24 hours despite the fact that no new signups have occurred and my few users so far have not uploaded significant amounts of data. I thought it was old Snapshots being stored, but I deleted all but one of them and the total amount of data being used has not changed. Is there any way for me to find out what is using all this data? And why is my total available data not displaying correctly? Thanks.