Hi Meme,
This kind of is normal of any kid during the early (first few years) stages of a separation regardless of situation and especially in situations of abuse or with where one parent has not seen the kids for a while and is attempting re-connection. Try to think of it in those terms as opposed to the ASD. Any kid will find that situation challenging, though with the additional complications of an ASD they may be finding disruption of routine etc and also trying to deal with many different emotions and figuring out how to express it difficult. While you are facing a challenge, and clearly demonstrating acting in the interests of their welfare (the fact you’ve made provision for a special school, ensuring you go to GP if you feel the need to etc) I would not be overly concerned. While it’s understandable you are concerned, and feeling anxious, try not to imagine situations that haven’t happened. Deal with each as they come and play it with a straight bat. You are doing well.
I’m not sure there is much else you need to do right now as it sounds like you’ve done all you should. The best thing you can do right now is cut yourself some slack and pat yourself on the back. You are going through a difficult time and you just need to hang in there and keep doing what you’re doing which is focusing on the welfare of your children.