HTC Eris :: Low Storage On SD Card?

So I have been quite perplexed as to how my SD card was filling up so quickly. I would try out a ROM for a while, make a Nand backup, have about three of those on the phone at a time, always making a copy onto my computer. And yet it seemed like every time I deleted old Nands and ROM from my phone, my space continued to get smaller and smaller, until today I was down to 900 and some odd megabytes. I don't have that much music or other media stuff on my phone, so I plugged my phone in, went through and deleted more music, videos, etc. off of my phone. Turns out, while I had my phone mounted (I use a Mac), and I dragged files from the phone into the trash can in the dock-- it wasn't actually deleting the files from my phone, but merely putting them in the "Trash" folder on my SD card. So I went through using Astro and deleted everything in there. AND I'm back up to fish gigs. not sure if anyone else might have made the same mistake, or if I completely outed myself as a NEW B, Whew, what a relief though.