I'm sorry you're feeling so depressed with all this pain. Please contact your counsellor or your doctor and tell them how depressed you're feeling.

Please believe me... your son would not be better off with another mother!

It's concerning to me that you're about to taper off your Nortriptyline while you are feeling this way and that makes me wonder if your Doctor is fully aware of how bad you're feeling to suggest this to go ahead tonight. Personally I think it is really important that you verbalise to your Doctor the thoughts you've written here in your post.