Disturbing Drunken-like Behavior

[Reptiliancousin]

Long time no see folks! I just bought two different species of garter snake from the same pet store and both were housed together. Well after more close observation I noticed the larger acting sick. Very quiet, not at all very active. I noticed a little bit of this yesterday when I looked at her. The post gets it's name from her unusual floppiness. She falls backward and moves in circles. But this repetitive movement of upside downness has me highly concerned. It's like she's devoid of energy and just lets her body fall wherever it wants. But she moves halfway sideways and always falls upside down. It's almost like she's blind. But she follows movement in front of her so I ruled that out. When climbing on her tank she fell down and again landed upside down. She stayed that way for minutes until I turned her back over. It's like her brain is lopsided. I also noticed some bulging in her body. Do any of these behaviors sound familiar? I'd like to know if there's anything I can do. She has recently ate some pinkie pieces on Friday. My gut tells me these bahaviors are too extreme and she's going to die. I've never seen a garter so hum drum and 'dizzy'. I can post more pictures if needed. CornsAndGarters 034.jpgCornsAndGarters 038.jpgCornsAndGarters 042.jpgCornsAndGarters 047.jpg