(((((hugs)))))
Of course you have had meltdowns!! ANYONE would in your situation. I was fired once, and truly thought I would NEVER get another job. My company did it to a LOT of people, close to seven percent of ALL employees, at the same time. Each and every one of us had taken disability leave for some problem, and even maternity leave was counted in this group. The CEO and majority owner flat out told the local paper that we could go ahead and sue him. He had more lawyers and better lawyers and would drag it out and spend very penny he had to make sure that if anyone got a dime out of this, it owuld be their great grandkids. It wasn't published, but I know the reporter he said it to - it was a cousin of mine!
Please use your tools to help you get through this in the healthiest way possible. You have worked with a LOT of tdocs and psychiatrists, and they taught you a LOT. Think back on those lessons and the tools they taught you to use, and go back tos ome of those things. Look for a NAMI group and even if you have to drive an hour each way, go to those support groups for a while. Go to your doctor and see if your medications can be tweaked a bit, as that may also be a big help.
Do NOT worry about a reference. Head Start CANNOT give you a bad reference. If they do? Get a lawyer. I am NOT joking. Legally if they do ANYTHNG other than confirm employment dates, they can be sued. Saying ANYTHING negative is seen as 'black balling' and is very very illegal. MANY companies instruct managers not to give ANY info other than employment dates because even if YOU think it is praise it could keep someone from getting a job. I once didn't get a job because a former employer said I was very bright and curious. The company I applied to didn't want those things, they wanted someone to do exactly what they were told and nothing else. it was a telemarketing job and they wanted someone to only say what was in their script, to not ever deviate even one word off of that script no matter what the caller said.
I would let the HR person do her job and talk to the honcho. Forward her your fb page with comments from other people. If nothing comes of that, tell people in the community, esp parents of head start kids, ALL that the driver is doing and encourage them to complain about her. I am sure some parents will be IRATE over these things and will shake things up a bit.
I am so sorry this happened, but you ARE in good company. LOTS of us have been fired wrongly for other people's lies and manipulations. You WILL get through this and you will find meaning in your life again. And meaning in your person. You are TONS more than this job, and they should have been thankful to have you, esp as you put up with this driver!