I would start by calling the school counselor and pushing the process to have your daughter tested for special education before school is out for the year. The tests they do will show what exactly your daughter's learning disabilities are and then an IEP (individual education plan) can be put into place for next year. With this IEP in place, she'll start jr. high school with the tools in place for her to be successful in school.
Once you know what your daughter's disabilities are, you can start educating yourself on how to best support her at home, over the summer, to build her confidence back up. Let your daughter know that learning disabilities are really nothing more than learning differences and it's up to the two of you to make sure she learns the coping skills she needs to be successful in school and in life. These differences are a challenge, not an excuse.
I've taught jr. high and high school for 16 years and I've seen many students like your daughter come through and be successful. These are the students who understand their differences and how to advocate for themselves when they don't understand. I'd like to tell you that all teachers have been trained on how to best help their IEP students, but the sad truth is, many aren't or they won't. That's why it's vital for your daughter to learn how to speak up for herself in a respectful way.
Feel free to email me back and I can tell you all the "tricks" that I use in my classroom that help my IEP students find success in my classes (history and personal finance). But, without the testing and the IEP, you won't have the weight of the law behind your daughter to get her the education she deserves.
"No Child Left Behind" is education's double edged sword. It requires educators and parents to demand a lot from their students and it demands that educators and parents find ways to make learning happen. No more excuses on either side of the learning fence! All children are educable. We, the educators and parents and students, just need to find the key. In some cases, that takes blood, sweat and tears. But, the rewards--a successful human being--are worth it!
Good luck!
PS: Just be aware that most bosses in the workforce aren't going to care about your daughter's learning differences. Either she can do the job or she can't. This is yet another reason your daughter needs to learn coping skills and self-advocacy.