hi Crawling. Sorry, it was all several years ago now. The BPD swings highs & lows more I suppose like rapid-cycling bipolar, however, the difference is not due to chemical changes sweeping through the brain - just the inability to regulate emotions. So you can be having the time of your life, someone calls you a "fat cow" or you have a row with your mum, or someone says something at work - an external trigger I mean, will make you feel very, very low.
I took anti-depressants and mood-stabilisers to try and stop me veering to either extreme. But of course, and here's the nub, chemicals can't "fix" your emotions. I got to using for example, the Zyprexa, when I knew I was going batshit crazy and about to harm myself - I'd pop a pill and be asleep within 30 minutes and so I couldn't hurt myself. :(
The Zyprexa did of course help with the psychosis - in my case the disassociation. For example, I'd get in the car and I'd sit down and not know how to start the engine. Or I'd be somewhere (near home) and not recognise any of the streets or buildings. Or I'd not know my own name. These episodes (for the best part) lasted only a couple of minutes, but they were mentally exhausting and frightened me.
So, I suppose my scale was more about feeling in control and stress.
When my stress levels are up to 3, everything's hunky-dory. When they're 4 or 5 (difficult day at work, big bill comes in, horse hurts itself type thing) - it's manageable but I need to immediately take stock of the situation. I used to be awfully good at sticking my head in the sand, wheras I need to "fix" the issue right away to preserve my sanity. E.g., if I get a big bill in - no point pretending I didn't and kicking the offending letter under the couch never to be seen again.
It needs to be paid.
Even now I get very jittery and uptight if the bills aren't paid IMMEDIATELY. 
When my stress levels reached a 6 or 7 then I'd need to call the psych team to talk me down because there was no coming down from 7.
Having animals was an enormous help and I'd dare say quite a few times they stopped me committing hari-kari.
I would not have been a good mum before therapy. I took too many things personally and would fly off the handle. These days I'm much better at distinguishing when something is my fault and when someone else is to blame. I'm much better and saying "you're being a tit, but your behaviour and attitude is no reflection upon me". I'm also able to open up to my boyfriend wheras 10 years ago I think I must've been a psychotic nightmare to live with... mind you, being a psychotic nightmare I didn't attract "decent" men so they probably got what they deserved! 
The roots of BPD seem to lie in PTSD of our childhoods. As a child you are not to blame for anything (within reason obviously!) - and the real healing starts (with Schema Therapy at least) when you're able to say "mum, you were fucking horrible and yes, you did abuse/neglect me". But alas, I've seen many BPD women idolise their childhoods when it's blatently not true. It's hard to admit you were abused as a child. Nobody wants to say "yes, I used to go home from school on a friday night and nobody would talk to me until monday morning". NOBODY wants to realise and admit to themselves that they lived like that.
My mum gets sharply told to "fuck off" every time she steps out of line these days. There has been a definite shift in power and she doesn't like it! 
But there's also the realisation and acceptance that although my dad wasn't abusive, he was passive - and therefore allowed my mum to be a prize bitch, so I've had to accept that he is a "weak man".
There's plenty on the "Stately Homes" threads about being the children of clueless and abusive parents.
I'm just happy that I know I've broken this cycle of abuse (my parent's parents were shit too) and that my son is loved, cherished and cared for.
But congratulations to all the BPD women here who live as normal lives as is possible - the majority of BPD women end up unfortunately addicts and/or prostitutes. :( So if you're awake and dressed this morning with hot water and a roof over your head you're doing great! :)