Was told that i have wisdom teeth but shouldn't that have showed up on my xrays?

Yes: Depending on which x-rays are taken. A panoramic x-ray or a full mouth series should show any wisdom teeth, even if they are impacted (have not erupted into the mouth). Bitewing x-rays may or may not show wisdom teeth, especially if they are impacted.

Not always: If the wisdom teeth are deeply impacted in the lower jaw or high in the upper jaw, the small bitewing x-rays or periapical x-rays may not show the impacted teeth. A panoramic x-ray would show the presence or absence of wisdom teeth in the majority of the cases.