Both thumbnails had a vertical split in the tips not deep, i noticed dark horizontal lines above the lunulae they don't grow anymore. only these two?

Nail changes: Are tricky to diagnose without a consult. Given the they are on both sides unlikely to be related to injury but this may need to be considered. There are a variety of other medical conditions that can be associated with nail changes and so seeing a doctor to run tests may assist with making a diagnosis. Have a look at this link for some general information: http://www.dermnetnz.org/topics/nail-

Nutrition deficiency: Most black lines on nails are caused by nutritional deficits. Most kinds of nail issues result from biotin, zinc, iron, and/or calcium deficiencies. In such cases, consult a doctor in person for a physical examination and take multivitamin supplements. Horizontal black lines on nails can be an indication of an underlying health problem, and should be evaluated in person with a physician.