I'm really glad you are going to contact them. My local Safehouse helped me with someone who was in another state. There is action they can take even when he is 2,000 miles away.
Harassment is still harassment no matter where he is. There is no state in the US that permits someone to repeatedly contact an ex-wife after she tells him to leave her alone. I hope the advocates in your area are as good as they are here - if so, they can help support you in a lot of ways, including emotionally, as you get through this and they can help take action up make sure he leaves you alone.
By grounding techniques I mean things like described here:
Link Removed. Thinking of a safe place is one grounding technique.
I like to hold ice or mindfully (noticing all I can about this present moment) hot tea when scared, or go for a walk or say the alphabet backwards in my head. Sometimes the panic doesn't get better right away, but sometimes it does. Sometimes it helps ride through the tough times.
For me, I can get almost frustrated when it feels like my life is unbearable to live for someone to suggest to go hold ice or do these other things. They are simply things to help get through this pain now until it gets better - and it will get better.
It sounds like you are feeling really hopeless right now. Are you having suicidal thoughts again? Don't lose hope - I know, it's so easy to say and so hard to do.
This would be so hard for me too. Please don't hesitate to reach out to crisis lines, here, and your therapist.