How do i proceed?

I am having difficulty understanding your position. You say that you only went to visit, so you didn't take your belongings. But, then you say you can't make the court hearing because you don't live in the US anymore. So I'm not sure which is correct, and I can't properly address the issue of your belongings.

As for the mental cruelty, the only reasons lawyers use that is because the state of Illinois doesn't require parties to wait 6 months or more to get a divorce. Mental cruelty allows the parties to be divorced as quickly as the first day the parties can get into court. If you do not make it to court on the chosen date, the court will grant the divorce by default. You will then have 30 days to file a Motion to Reconsider based upon the default divorce. The issues of mental cruelty do not show up on any other records, nor does it truly matter in a real sense, if you want the divorce, which you said that you do.

But, if you want the divorce, but need to get your belongings, and will return to the US, your best option is to file an Appearance, and file a Motion to Continue to a date when you will be able to appear in court.

From an emotional standpoint, I understand why you're upset, and why you feel those allegations are completely untrue. I always recommend that anyone going through a divorce, find some kind of counseling. Divorce is emotionally draining. The person that told you he would love you forever, has now told you he doesn't love you anymore. That hurts. Please do yourself and your child a favor, and find a therapist. The right therapist will help you become a happier person, a better parent, and a better relationship partner.

Also, make sure you do something about getting your son to see his father. That child deserves to have both parents in his life.

Good luck