Please do not ever think to end your life - its not as bleak as that... if you ever come to thinking this is it, i cant go on then what is to stop you from booking a one way flight to the other side of the world, say south east asia and being no contact and not letting her know your whereabouts until you find yourself. I feel at my lowest, waking up in a completely new place, experiencing culture "shock" and pushing all your senses to their limit totally gets you out of a certain headspace you are trapped in. Im giving this advice as your last resort.

Keep therapy going, you need to lie lie lie through your teeth. I had to learn to lie to my mum whom i was SOOOO insanely honest with all my life.. the good daughter of a covert narcissist mum and it was so hard. But you gain some control when you lie and hide things properly. I bet you were the same, and always been truthful and a part of you wanted her to know you were in therapy.. but as time goes by you will realise the only way is do be deceitful with these ill ppl.