Well, clubbing of the nails is generally related to a cardiac (heart) or pulmonary (lung) problem, but can occur also due to nutritional and environmental effects, as I said. The fact that they are pink is a great sign. As long as it takes less than 3 seconds for blood to return to the nail bed after pressing on it with your finger, your oxygen level is normal.
Vitamin B12 can be supplemented to help this problem. Even if your vit B12 level is normal.
You should also have your 25-hydroxy-vitamin d level checked. Many people are deficient and it can affect the nails, the energy level, the skin, sleep, bones, aches,pains, depression, etc.
You should be sure your thryoid is normal and that you are not anemic, as these can both lead to nail abnormalities.
Finally, you should be sure you are moisturizing your hands and your nails. Cuticle oil or olive oil can be rubbed into the nail itsel, which will help strenthen them and grow straighter.
Here is a helpful site for you:
Hope this helps! Please "accept" and let me know if you have any follow up questions or concerns.