Sounds like a deficiency or stress.
Pester your GP and ask to see a doctor not a nurse or chemist.. Call LIVI online doctor if need be. then you just show your nails to them using your phone.
No wait no hassle..
Mees Lines if side to side
Mees’ lines are white lines or bands that appear on the fingernails or toenails. They can be a symptom of an underlying health condition.
my.clevelandclinic.org
or
Muehrcke lines are paired white transverse bands that span the width of the nail bed and run parallel to the distal lunula. They were first described in the fingernails of patients with severe hypoalbuminemia, some of whom also had nephrotic syndrome, which resolved with normalization of the serum albumin level. Muehrcke lines have since been reported in patients with liver disease, malnutrition, chemotherapy, organ transplant, human immunodeficiency virus (HIV) infection, and acquired immunodeficiency syndrome.
3,
18 They are associated with
periods of metabolic stress, ie, when the body’s capacity to synthesize proteins is diminished.
Here's a page with types of nail problems
Nail lines are a common presenting finding. A thorough inspection of the fingernails and toenails is an integral part of the complete physical examination. An understanding of basic nail anatomy and familiarity with several basic types of nail line enable the clinician to diagnose and treat nail...
www.ccjm.org