Trouble with getting a diagnosis of SPD for daughter

Good Afternoon,

My name is Amanda and I have a 6 year old daughter that I believe has been struggling with a SPD or Autism since birth. Ill give you the fast and short of our concerns, although the list is quite long...

She had fine motor delays since birth, she didnt sit up until 10 months, walk until 18 months, as a baby and toddler should would bite me when she was angry, she wasn't potty trained until 4 years old, had to do physical therapy to help her hold a pencil and do the other fine motor activities that my 2 year old now does...

She is forever drooling, like she is afraid to swallow her spit, but has no trouble eating, but refuses to eat with a fork and most nights uses her hand for even her salad...She has a blanket that she has to have when at rest and will turn the blanket so she can rub the blanket in the same spot, she is a hand flapper, she bites her fingers and her tongue, doesn't listen, smiles when she should be crying and I have only seen true tears 4 or 5 times, she interrupts conversations and makes a tantrum out of something as simple as a request to put on a shoe, she picks fights and smiles. She listens to the TV so loud that Im sure the neighbors can hear it 5 houses away but will stand directly in front of the TV (while flapping) and refuses to turn it down

She can walk around with food on her face and hands, her shirt tucked into her pants, her panties sticking out above them and just be as happy as can be...

The odd thing is and what throws me off, is she is incredibly smart, reads like a champ, is very inquisitive about the world and has a memory for life details that shock me

and to think, this is the short list....Im frustrated and aggravated and we have tried the pediatrician, the school, and a counselor and everyone tells me she is fine, but only spends a short time with her....HELP...What is this???? How do I get someone to help???