Start to find out about your family history. As you go back in timet you will uncover a new surname (female) at each generation and no doutbt like most of us you'll find a Jewish name arises.
If your serious, then go with Segilla, you are Jewish through the Maternal side, reason is, pre dna, youcan always prove who your mother is, apart from looks, you can never prove 100% who your father is.
possibly you have russian Jewish great grandparents who arrived here in about 1919 or so escaping persecution. You may not realise that as the surnames were changed from the Russian names on purpose and not just to make it easier for the spelling.