Sigh...there's always the "no drugs" crowd.
As someone who was diagnosed at age 8 with ADHD, and whose sons both have it (my 11 year old has severe ADHD, 10 year old has mild ADD), I get tired of the "you're bad for putting your child on drugs" nonsense. If your child had a seizure disorder, would you withhold medication? Seriously?
Aaaanyway, J., I feel your pain. Starting on meds is a hard and worrisome journey.
Be very open to the fact that Focalin might not be right for her. Or the dosage might be too high or low. Or she might be having withdrawl symptoms when she comes "down."
Also, be CERTAIN that she's getting it first thing in the morning. Taking it later will cause it to wear off later, and it will be harder for her to eat dinner or go to sleep. The weekends are a good time to pay attention to the "coverage time" of her meds. You'll see when she's the MOST focused, when she's the least focused, how long it takes to kick in and wear off (Vyvanse, for instance, took almost 2 hours to kick in for my son). Then you can give it to her at the proper time so you'll know she's covered at the most important parts of her day.
If Focalin is causing problems now, it's not going to get better. It's a stimulant medication. Unlike Strattera and Intuniv, which need to build up in the system, stimulants work at their full potential for just 4-10 hours, depending on the drug. So if she's having these side effects, I don't see them improving. She needs to try something else SOON and get her balanced, or it's going to be VERY difficult to get her to be willing to try something new. She'll fight taking the drugs because of the negative side effects.
So talk to her doc about trying something else. There's no shame in that. We started with Strattera, which didn't work for us (and made DS2 depressed), then went to Vyvanse for DS1, and then added Intuniv because he had withdrawl symptoms each night. Finally Settled on Intuniv for DS2 and Adderall XR with Intuniv for DS1. They're both doing wonderfully on them, but it took time and trial-and-error to get to this point.
Also, I strongly recommend that you take her to a counselor who specializes in ADHD. You BOTH need tools in your toolbelt to adjust and adapt.
And pick up the book "Love and Logic." The fact that you're arguing with her tells me that the skills found in L&L would really help you.
♥