My big toenails have been going bad for a while now, for reasons I'd rather not get into it's probably a result of poor trimming. At any rate I decided to just leave them alone for a while. The left one has hardened and turned white (like it's one big cuticle) and the right one (the worse one) snapped off (but there's still a little bit of nail left). I'd heard of toenail fungus but I didn't think that it was what might be wrong due to the nails not looking particularly infected or yellow/brown but rather malformed and dry. The more fool me as these seem to be symptoms of a fungi. There's white dry bits beneath the nail that come loose quite easily and some are a little yellowed.
Though I know it's stupid I feel a bit embaressed to go to a doctor about it but I've heard you can lose your nail completely to fungi. Thankfully my other toenails are fine for now though so it doesn't seem like it's spreading but I'm not sure if it's going away and if my other nail is ever going to grow back properly.