
The answer may be both. Sometimes they can have a false strt, and appear to come in season, then stop and start again properly. Probably not a high enough concentration of hormones to get things going initially. I would treat her as being in season for at least 3 weeks from when the bright blood started.
You will probably notice that she will now get much more swollen, and it is best to treat her as in season until all the sweling and open look to her vulva has gone.
She will never be quite as small ther as before, but you will be able to see that she is tight and not in season.