I think EC bunnies develop weakness in their hind end..especially their left side? I think. I'm no expert on EC but it sounds more and more like it. I'm sorry she has gotten worse
I'd keep persisting if it was me, I think they generally get worse before they get better. One of the buns at the rescue I volunteer at developed head tilt, she wasn't rolling but her head was basically sideways at one point
Took her a few weeks but you can't even tell it happened to her now. Whether or not that was EC I don't know but I'd think keeping going with treatment for a few weeks at least is worth it unless she is very distressed.
Sending lots of vibes her way )))))