If i had genital herpes, how did i get shingles?

Not related: Genital herpes is caused by herpes simplex virus i or ii. Shingles is caused by the "chicken pox" virus, which is also a herpes virus (herpes zoster). The only people who get shingles, are those who have had the chicken pox.

Different virus: Genital herpes is caused by a different virus that causes shingles. These 2 viruses are not the same and have have different clinical manifestations. Shingles is a future outbreak after getting chicken pox as a child. The chickepox virus then resurfaces and becomes active again but now in the form of shingles (not chickenpox).

Chicken pox: Genital herpes and shingles are caused by two different virus. Shingles is caused by the chicken pox virus that has been re-activated in a nerve root.