Nails curve up and down at the same time?

[Hango mango]

My index finger nail unreasonably bends down, makes a curving finger and also my thumb. But my middle finger nail looks like it’s curving up. It happens to other nails, too. Some of them curve up and some bend down. The pinky is the most normal. Please help me. It is so weird and uncomfortable. Thanks

 

[NailtechJoe]

Have a read:

https://en.wikipedia.org/wiki/Koilonychia