is this signs of autism?

I posted on this a while back when my child was diagnosed with hypotonia. At that time she was doing a lot of sitting on the floor flapping her arms and banging her feet.
Since then she has developed more and more stims (as they call them). She will look through a book and flap her arms and make the same shape with her fingers over and over again, while making the same sort of humming noise. If i go over and try to stop her she goes crazy. If i call her name she doesn't respond and seems not to hear anyone around her! She also spins in circles, either with her eyes closed or looking out the corner of her eyes. Her most recent one she has developed is to pace the same peice of floor over and over again, she also does this with her eyes closed, looking to the side or whilst flapping her hands. Lots of times we shout her she never responds and for a part of the day seems completely in her own world! she also suddenly starts laughing for no reason at all.
The thing is sometimes she comes out of it. her speech is coming on and she can tell you lots of things she sees in her books, but actual conversation is not there as yet. She hates transitions, completely hates them, to the extent i can get bitten, headbutted etc. She loves to play chasing with her brothers but doesn't play any imaginative games at all.  She is now nearly 3... and things seem to be getting worse, instead of better..although she can now walk. Which is amazing!! :)
I have never seen another child doing the stims she seems to do and it is extremely worrying for me. I have to wait another 2 months to see the head peadiatrician, so was looking to see if anyone knew what any of these could mean and how i can go about trying to get her out of it when she goes?
Thanks in advance
Maisy

[maisy2000]

just realised that this is in the wrong section.. I have moved it,, sorry about that