The hyper feelings and thumping heartbeat are oh-so-familiar. Possibly they are due to cortisol. I don't think you have anything to lose by trying ashwagandha. You know what else helps me a lot? Bach cherry plum flower essence. I keep a bottle next to my bed and when I have that heart thumping at night, I put 4 drops under my tongue. When the issue really is cortisol, it calms things very quickly. I've got quite an arsenal LOL. BTW the ashwagandha I take is a powder in a capsule rather than a tincture, so I can't comment on that, but I'd be interested to hear how you get on with it. I certainly wouldn't mind finding a cheaper way of taking it, what I have is Solgar (never cheap here), about £14 for 45 caps.