You poor thing! My fingernails mercifully were not bad at all, close inspection showed a slightly tan colour, a pale version of a smoker’s fingernail but nothing worse. My toenails were white, brown and black and while none of them came off, some nails thickened and split, like veneer left in the rain. Over six years later a couple are still a mite odd. At least I could keep my toenails more easily hidden, although visits to spas and pools almost needed a sign - ‘I do not have a fungal disease!’ I never painted toe or fingernails, which I have occasionally thought was a mistake but maybe not. Even normal polish affects my toenails if left on for too long now. If the thumbnail doesn’t come off of its own accord, it may need to be removed by your doctor. Best wishes.