“I am newly separated and completely overwhelmed with all of the stupid little things that I never thought of previously, like do both parents have to pay school fines if separated? What if my daughter still wants to do a family Halloween costume this year? Will she understand if her birthday cards are not signed from both mommy AND daddy (or should I even still do that)? I suppose I am just exhausted and am looking for some advice/support as a newly separated mother. I’m also on the spectrum, if that makes a difference.”

I am so sorry that you are going through this. It is totally normal for you to feel overwhelmed. All those little things are a lot when you add them together!
One important thing that you must remember is that divorce is not bad for children per se, what can be negative for your children is if your ex and you have a very conflictive relationship. I know that it is not always easy, but as much as you can, try to get on well with your ex for the sake of your children.
I strongly recommend that you and your ex create a parenting plan. A parenting plan is a document where you both agree on all these issues that you are mentioning. This way you create a clear set of guidelines and avoid future disagreements. If you get on well, you both can do it together. If your relationship is not that good, you may need the help of a family mediator or a lawyer. You can find two parenting plan templates in the first link below.
Finally, please remember that this is a very difficult moment for you. You need to be strong, because you deserve it, and because if you are not strong, you won’t be able to take care of your children. If you need 1-2-1 support, please do get in touch with me. I am here to help.
You may also find Support Pay useful to organize your finances. All REC Parenting customers have a 20% discount using the code: SUPPORTPAY at checkout.
You may find these REC Parenting articles useful:
Create a Successful Parenting Plan (& Parenting Template Ideas)
Should We Divorce or Stay Together for the Kids?
Magpie Parenting: What Is It About?
Lots of love,
Ana