rojon I've read the thread, hope I haven't missed something, but so far I haven't seen a reference to the possibility of Reynaud's syndrome. It causes poor circulation to the extremities, i.e. hands n feet. You mention having very cold/blue hands as a child. So did I, my fingers would go white with cold when swimming. It wasn't diagnosed until I was in my 40's and being investigated for various auto immune conditions. I took medication for Reynauds for a while, but found the head aches caused by the meds worse than the cold hands and feet.
I try and help poor circulation by walking, yoga and keeping as active as I can. When walking during the winter I wear thermal underwear (including leggings) silk gloves and socks under thermal socks and gloves. I empathise with feeling cold, it's misery making. We put the central heating on over the weekend because it was so cold, wet and gloomy here.
I support others who've suggesting a chat with your GP about this.