Dear Sunflower, what a terrible situation to be in! You are strong beyond belief, the fact that you tried to pull yourself together in this situation and reach out to hotlines for help speaks volumes.
Are you able to get some rest? You have done what you can do immediately, so take a few moments to focus on building on your strength so you can cope calmly and with hope. What gives you peace? Exercise, praying, taking a walk, think of something you can enjoy that stops your mind from freaking out. As a partner of BPD I have many such go-to methods or else I would not cope. One of them is to put together a playlist of my favourite spiritual music. I tell myself "I challenge you to listen to the end of this list and still be depressed". Never fails.
What simple safety precautions can you take while you are busy sorting this mess out? Does he still have keys to the apartment? It might be best to avoid being alone with him when he is dysregulating, if possible meet him in a public place or ask a friend to come over when he is coming around.
You are going to be OK. Hang on in there. Do check back in and let us know how you are today.
Big

Khib