I was a single mom with a daughter like this, so I definitely get the "feeling alone" aspect too. It's really frustrating to get diagnosed, because it does take many doctors' visits, time, and energy, plus UNLIMITED patience!!!
Here are some things you may not have thought of...
Easter Seals- there is one in our area that I hear FANTASTIC things about, and they have support groups for you, her, the family, etc. as well as classes... the list goes on. They also have OT, etc.
Hippotherapy. There is a horse therapy program in Winfield called FTEA (Friends for Therapeutic Equine Activities.) My daughter rides there and they are AMAZING. So many of her sensory issues have been helped thought this alone!!!
Getting a neuro-psych eval- this can help with learning disabilities, and whether you use that for an IEP/504 later for her in school, it definitely helps YOU as a parent learn how SHE learns and how to best approach her. We have seen Dr Appleby in Oak Brook, but I hear there is a fantastic woman at the Clarus Center in Warrenville (and we plan to do another eval with her this summer since it has been a few years.)
There is an excellent neurologist at CDH, Dr. Sperry. He works with special needs and Tourette's kids, so if you haven't gotten and EEG, etc and things and she "spaces out" and you have ANY concern about her physical brain function or possibility of petit mal seizures, etc. He is THE guy to see. (We've been through 4 neuros and he's amazing.)
If you haven't done anything dietary, I would definitely try that as well. We started off using the Feingold Program (feingold.org) and LOVED that it increased her attention span and really helped curb some of the aggression we would see when she was overstimulated. Red #40 was a BIG problem for us, as were apples-- of all things! We kept going and are now gluten-free and white sugar-free, and it has been a real journey to learn what food triggers she has, but WORTH it! (I have a food blog with out story and recipes, etc. here: www.chickiepea.wordpress.com.)
I don't know if I can really help with getting your husband on board, other than explicitly telling him (when calm, not in front of her, and when you have lots of time to talk....) specifically what you need. Not "get on board" or "wish you'd care" but a list of things to do... like: I really need you to call and make these appointments and then go with me to them, etc. Men work better with concrete things to do, not vague things. Then email him or make him a written note with them after you discuss it.
Whatever you do, don't give up on digging for answers. The biggest thing for me was answering "WHY" and it took me 7 years to get a diagnosis at all (PANDAS) and another 2 to get a dx of Lyme Disease. My daughter is 90% better between treatment for Lyme, dietary changes, some homeopathy, chiropractic (highly recommend again!), horse therapy, etc. Yes, we do/did A LOT, but it does get better as you learn more and more.
I did not look to see where you are, specifically, but there is also a homeschool group in the St Charles area that has a lot of kids with sensory issues and other "invisible" special needs, which I have found to be a wonderful community for us. I can give you that info by private message if you would like. I'm actually happy to talk with you about anything I mentioned here :)
You're doing a great thing by getting her help. YOU are her best advocate, and better to have caught these things now and fought for her than let things spin out of control for her later.
Hugs,
M.
PS- Another great book is "Is This Your Child" by Doris Rapp, MD. It discusses allergies and how they affect our children. I found it really riveting and it's an easy read (not too medical.)