That is a serious situation. You should consult with a family law attorney immediately about getting a restraining order / order of protection.
If this answer was helpful, please mark it as helpful or as a best answer. This answer is for general education purposes only. It neither creates an attorney-client relationship nor provides legal guidance or advice. The answer is based on the limited information provided and the answer might be different had additional information been provided. You should consult an attorney.
Follow the courts relocation language which usually requires a 45 day certified mail notification of your new address and phone number to your ex. Read your last agreement and court order and follow the language exactly to prevent your possibly loosing custody.
There are many factors that can affect how best to handle this matter and the best advise is to hire an attorney immediately. Unfortunately the advice above is a guess that is based on very scanty facts. Circumstances of all sorts can change the ultimate answer you need. If you want to know how best to handle the situation, make an appointment with an attorney and get good solid advise based on more exact facts. The money spent might give you the peace of mind you need.