It looks like folks have given you some advice ... &/or suggestions as to why your snake may not be eating.
I would have suggested not doing the natural warming but, rather, thawing it out in warm water. Then, making sure the entire mouse was pretty warm prior to feeding ... or to try smaller prey item/s ... or to try washing the prey item (with just a drop, or two, of something like Ivory soap and rinsing very well) ... or to try live.
I have an almost two yr. old female who had never been fed live but, suddenly, she will only accept live these days (was a last resort after all else failed). Hope is to convert her back to f/t.
If your snake is, actually, a male ... then, yes, he could just have "spring fever" and has other things, on his mind, than food.
Don't know if she may be gravid but, yes, a female snake can go off her food well before laying eggs (if she were gravid). As an example: I have a female who will lay eggs (or slugs), each year (even without having been bred), and she goes off her feed for one month, or a bit more, prior to laying. She, also, gets very active (of course) just prior to laying.
This is, however, not the only cause for a female to become very active. I have "another female or two" (confirmed female/s) who, also, become/s very active (more than usual), around this time, without being gravid.
Another factor could be viv temperatures. If the temps are not appropriate, it could make a snake go off their feed.