Anything with “d” does a number on me......feels like I’ve taken speed and it’s a disgusting feeling which brings back haunting memories or bad choices I briefly made in my early years. Like you OP, it’s also the only thing which really helps my allergies. I have TERRIBLE allergies with lots of itching on my body and feeling or having fuzz up my nose and behind my eyes. I also take a nasal steroid and that seems to mess with me too.....if I take the D for a few days it gets worse and my sleep gets wonky.....it’s TERRIBLE how everything that actually WORKED causes such horrible side effects.