Hi Sarah,
I'm sorry you're having to go through this. My sister is going through the same exact thing at the moment and it's been a rough time for her. I also work with children with autism, and I have to say that speech therapy does help, as does early intervention, so be as proactive as you can. Ask any questions that you can, even if they seem stupid.
You might want to ask if there's a class to learn the Hanan Method or google it. Speech paths use it sometimes to help babies and children's speech.
I used to teach in California, so I know there's a lot of support for parents of children with special needs. You should be seen by someone soon and get an Independent Family Support Plan set up within 30 days of having been seen by a specialist teacher.
Get a speech pathologist recommended to you from the doctor and ask around. Generally, ones with waiting lists tend to be better.....
Best of luck for you on this journey. I know it can be hard, but if you put in hard work now, it's worth it!