Hey Fearless, Just came across this post of yours. The meltdown is over at this point (at least that one) and you made it through that hard time. You are strong and will continue to be strong for your son. Each day, each moment, will go by. Continue to help him as best you can. Hopefully, as he grows older he will learn strategies to help him to deal.
So much easier said than done, but try and get to a place where you can distance yourself from the meltdown and not get sucked in to the drama of it all. At some point it will pass. You are a good, strong, reasonable mother. He will make it through the trials he has.
Be good to yourself. Take big, deep breaths and repeat in your head that "This too shall pass. In time, all will be well."
You are in my thoughts.