Two things: one, when I took Vitamin D (as GP said a few years ago it was very low), as its a hormone, it caused me to bloat up as if I'd taken steroids and imbalanced me further so I had to stop. My last Vit D test was normal so I'm wondering if its linked to oestrogen levels being that's its actually a hormone and not a true vitamin. NICE seem to have had a campaign to get our D levels up as my friends were all told their's were unusually low when they were also randomly tested after visiting for something else. Or it could be that, like a lot of drugs including anti nausea meds, the Vit D is a stimulant and adding to the nervous system effects.
2nd thing: That does sound like a benign tachycardia. I was whisked off to stay at my aunts for a week when I was very bad and they took me to their GP and I could barely walk from the waiting room to the office. The doc wasn't even slightly concerned though, he took my pulse and it was about 120bpm and he didn't think this was a sign of anything sinister. I asked if I could be referred for an echo cardiogram and he said it was pointless as it was just a tachycardia. He did do an ECG as they had a facility there and it was all normal and he was the one who gave me beta blockers to take, as and when, and he told me not to take the Diazepam my GP had given me the week before as my issue was physical and not mental. At the time, I had suggested it could be caffeine withdrawal, as it was the only thing I could think of as I had not had any due to not being able to consume much of anything. He said it could be that or something else. If only he had mentioned hormones though!
I still get the worn out feeling and no motivation, but the over-stimulation tachycardia and adrenal anxiety has completely stopped (I just had a couple of tachy episodes for half hour a few days after stopping the pill) and so I'm trying HRT now to see if a small addition of oestrogen will bring my energy up.
Are you still on the beta blockers as remember you went back on them when we were discussing if you could have been going through withdrawal? Might be worth trying some HRT if that hasn't helped.