relive

To relive is to experience something again in memory. Relive the moment, relive the past, relive it every night.

It means feeling it again rather than merely remembering, which is the whole difference — and reliving a traumatic event involuntarily is a defining feature of post-traumatic stress, so the word carries real clinical weight. Of a happy memory it is warm. Note that relive is stressed on the second syllable, which distinguishes it from anything else.