Sorry it's feeling so overwhelming and dark right now. I think at different times, we've all been there.
You've already received excellent advice and feedback, so I'll just add some random thoughts that come to mind:
1. Grades are not a reliable indication of Giftedness. Many kids' grades are poor despite being gifted because content is boring so not worth the effort or because good grades are not a good motivator.
2. Check with your local bar association. They can often direct you to an agency who will do pro bono work.
3. Do your best to have your emotional melt-downs at home so that at school you aren't perceived as an emotional mother who needs to be managed but rather an informed mother who needs to be heard.
4. Even if you do choose to homeschool, consider an option that will allow you to still be a part of the public school's enrollment so that the door is still open at a later date to return and so that you have access to speech therapy, occupational therapy, etc. Many districts will allow a mix, so it is worth pursuing.
