snake in my bedroom..

[pixistyxa]

The other day I found a snake in my bedroom. I live in Southeast Michigan (just over the border from Toledo, OH) in a house, on the second floor. It was on top of a couple of bins I have that stand about 4 1/2 feet high. I have no idea how it got up there but I went to reach for something in the top drawer of the bin and came eye to eye with a snake looking back at me. I rarely even see snakes here, even in the yard let alone the house.

Anyways, I put it in a container and let it go in a corn field in the backyard and I'm quite positive it was a garter snake from looking at pictures, but I was wondering if anyone could tell me for sure? It wasn't very big at all but it was probably 2 feet long. To be honest, snakes really creep me out so I've been thoroughly cleaning my room and have found a couple of spots of something that look like bird poop, one spot is white one was dark brown and much more sticky looking, on both the bins and the wall. I'm assuming these spots are snake poop... the whole thing was just so, so very weird. I'm becoming concerned because the other week I also found an enormously large nursery web spider on the front porch and have seen several very large spiders since, so I've been cleaning like a crazy person..
The first picture is how I found the snake, the others are the snake outside in a container.