It's not just one day at a time, but also one 'bite' at a time and one 'step' (literally!) at a time . . . on some days, my dog has been the only reason that I've gotten out and done anything beyond what was necessary . . . sometimes it just takes identifying the 'right' motivator . . . even just resolving to do a little more (even if it's just a few more steps, a few jumping jacks, ANYTHING) than the day before would be a start!
You should also be pleased at such a negligible gain during the holidays, so take pride in that!!