I am no doctor, and if things are as bad as you say, you might want to go see one.
That said, when I first read your subject line, I figured it was just going to be a case of someone over nic'ing themselves, but reading further and further into your OP, i saw that you had already done the reading and tried to adjust for that.
Definetly give the WTA route a look. I have no experience with them, but I have read enough stuff from people who did go that route to see it took care of a lot of their "issues"
One thing I will throw at you though, is that maybe you arent
vaping "efficently" to get the nic into you, and that you arent absorbing enough nicotine, and things have just gotten worse as you went down in nic levels. Anecdotally, I know that when I quit cold turkey years ago, i was suffering sleep issues terribly. I wonder if maybe, in your anxeity to feed your "beast" you are hitting your ecig too hard and like a cig, and not getting the most out of your vapor
device. Since vapor is absorbed differently than smoke from a cig. Ideally vapor is better absorbed into the body (albeit slower than smoke is) through the soft tissues (mucus membranes) of the mouth, nose and throat. What you want to do, is slowly suck into your mouth, hold it for a bit, (optionally take a shallow 'hit' of it to your lungs) and then a slow exhale through your nose. Not only will this help you absorb the nic better, but in a way for me it is a bit calming, sort of like a meditative breathing exercise.
p.s. go see a doctor