Keep feeding her greens and providing water, you might also want to try the Oxbow Critical Care Small Animal Food to start making her eat a little more. My vet told me that with the CC you could prepare it and instead if syringe feeding her it, you can roll them up into little balls and let them dry a little since some rabbits prefer yo eat them that way.
Does the medicine have a label? If so, it should somewhere in the bottom right hand corner next to how many mm it is.
What I usually do with Runaway is have her wrapped up as a burrito with a towel with her legs tucked in. My mom will then hold her in a type of “hug” with Runaway’s back facing her. I would then give her the medicine through kinda of the back of her teeth (that’s what my vet told me) and squirt a little bit in there. Runaway will then start to move her tongue meaning that she has already taken it in, after she’s done I will then squirt a little more from the syringe until it’s done. One of you guys could also try talking to her calmly to try and keep her as calm as possible.
Runaway, with her previous owner, grew up as a “wild rabbit” so I get the whole “bunny jerking her head and not wanting to take her meds stuff”
?
But as you said you tried it that way.. so you could maybe also try putting it on her greens and see if she will eat it that way instead.
And no worries, with the proper care and you calling the vet about anything different going on and/or taking her to be checked, she will be okay hopefully
I also tend to get anxious when I notice any changes happening to my rabbit (like not eating or her being lethargic and looking uncomfortable).
Hope this helps a little