sick turtle :-(

Something is wrong with my dbt and the vet seemed somewhat clueless. This morning, I went out to check on her and half of her (a side, not a front back thing) was floating and the other half was staying submerged. When I picked her up, she was very limp. She normally fights and lifts her head and she basically could barely pick up her head. If fact, when I stuck her on the ground, she was like a ragdoll (she normally goes into a full sprint). She was also eating her water lettuce (which she never does–I thought that stuff was supposed to be terrible). She looks really weak. Her eyes are open, there is no discharge from any part of her. Her shell looks fine. The vet gave her Baytril but I seriously wonder if she’ll even make it through the weekend. I took her out of the water and have her in a container with the UV lamp. I gave her some veggies since she’s not in the water with her minnows. Yesterday and the day before she was fine and really feisty. She normally eats minnows, goldfish, and she ate a crawdad or two the other a week ago (she wasn’t supoosed to, my husband thought crawdads from the bait shop would make fun pets but the turtle thought otherwise). Any thoughts, suggestions, or advice? please? Rowena