My big toe nail fell off, seemingly for no reason. It was very brittle recently, and when I clip them, both my big toes are brittle but only the right one would have little parts "fall off". Then I noticed today that there was a large crack going through my nail about half way down, and I clipped it off. I only have half a nail now but clipping it cracked it again. (I put a bandage on it because I'm scared to clip it any more.)
I don't do sports, I don't wear tight shoes, and I don't wear dirty socks. The only indication that it is fungal is because it is brittle, but could that be from a poor diet, or dehydration? And what should I do? How should I prevent it for the other nail?