and log your progress learning German
The goal for tracking your German study time isn't actually to track the time--it's to track your progress. Minutes studied does not equal amount of German learned, and that's the key difference when you're learning to really operate in German. So first you need to concentrate on what you're doing, not how long you're doing it.
1. Count tasks, not time.
Go for an amount of learning sessions in a week, not minutes "studied." When you get away from time, the task becomes your priority and your brain can leave time alone. Time can become a huge distraction and it can seriously demotivate you if you're too concerned about how much time you're spending on a task. If you have an appointment, use an egg timer or the timer on your phone to remind you of the appointment so you can simply dive into the task and not worry about the appointment--your timer will take care of that for you.
This is a really difficult thing to do in our over-scheduled, over-busy lives where we rush, rush, rush from one thing to the next. Learning German is not to be rushed, it is to be enjoyed. Even if you only have 20 minutes, set a timer and enjoy those 20 minutes. You'll be so happy you did.