A workout routine or daily habit, it's difficult to start something new, but it's even harder to start something again. When we've already attempted the change, gave up, and are now trying a second or third time, that takes great will power.
When possible, do your best not to give up the first time. Momentum is a valuable asset, and trudging through a difficult season will ultimately be easier than giving up and starting again later. Press on, and let the idea of having to start from square one be motivation forward.
Also remember how quickly time passes. The days seem long and hard, but the weeks and months pass quickly. Imagine if you had kept up that habit starting a month ago. Where would you be now?