The first thing to do is--let go of the guilt! It's gonna happen. Especially at this time of year with travel and extra responsibilities added onto already insanely busy lives. The important thing is to get started again right away. And remember that the benefits you have gained from your practice are not going to go away.
Meditation teacher Shinzen Young is fond of saying, "If you can't be disciplined, be clever." Here are some hints you might try to cleverly get back on track with your practice.
1. Set a goal where you are sure to succeed. Even if you were meditating 45 minutes twice a day before your practice stalled, when you restart your practice set a goal that you know you can meet, say 10 minutes, 5 times per week. It will allow you to feel good about your practice again and will help you build momentum naturally for longer periods of practice. And you might want to reflect if you stalled because you were biting off more than you can chew in terms of time spent in practice for your current life and circumstances. It is exponentially more effective to practice regularly for shorter periods of time than to practice for longer periods of time irregularly.
2. Make yourself accountable. Make a deal with your sangha, spiritual director, life coach, teacher or a friend that you will let them know that you have met your goal. Do this weekly, or even daily, until your practice is re-established. It can be really simple like sending them an e mail or a text.
3. Is the reason you are not practicing is because you are bored? There is no reason to be. A conversation with an experienced teacher can help you identify ways to modify or refine your practice so that you will be energized again. You may also try some of the many guided meditations available on line. (See my Youtube channel for some of them.)
4. Last, but perhaps most important, many times we stop practicing because our practice is about to reveal something about our lives that some part of us would rather not look at. If you go ahead and practice anyway, you will probably find that what is revealed is not nearly as scary as you unconsciously feared. So, if you become aware of the need to practice, but you find yourself resisting, check in mindfully and deeply for a moment to check if there is any reason for the resistance. It will be enlightening.