lexicat,
Welcome back! Wow, hun, that sounds so difficult being in a foreign country without support. It's no wonder you're struggling. Moving is hard enough, not to mention a language barrier, parenting, and facing your past.
Up In the Air gave some excellent advice, like finding an English speaking group, and maybe even an English speaking therapist. Are there any parenting groups in the area that you could attend to meet people? You're not alone. It's tough being a parent, and everyone needs support raising kids.
I'm sorry for your loss, too. I can understand why you'd reconsider NC. Is there a way you could allow them communication with you and your son that you feel would be safe and acceptable? What you told your son about your mom is a good balance - it's not too much for him to handle while giving him an age-appropriate reason.
Keep posting. We're here for you. Sending you lots of caring and support.