Yes, my boyfriend did that once. Pounded on the door and followed me around the house harrassing me. I had never felt scared of him before, but that definitely put me on edge. He disrupted the entire household including my then 18 month old son. I am sure it was for different reasons but the end result, was the same.
It is hard to see someone in this kind of a state, and it is hard to accept what they have become. Though, in my reality, it is not hard to actually SEE him in this light as this IS who he has become. He is no longer the mellow, fun, cavalier guy I met, but someone I'd rather not know.
It is good you are coming here to vent and get it out. There are so many that have great, solid advice. The words you read on here will start to silently guide your train of thought. It took a long time to get where you are and it does take time to slowly dig out the 'real' you again. This is the case for me anyways.
Go out, go shopping and have fun. In the future, my recommendation, is don't give him any ammunition to torture you with by telling him you are going to do something with your friend. Just go when it is time and don't make a big thing about it. That is the way I have been handling things in my own life. Gosh, does it take patience and practice, but I am finally starting to get it.
I am saying prayers for you and your children to find peace in this situation. Please keep reading and posting and really reflecting on the advice given, it has been a literal life saver for me.
Peace & Love
A.