Have you ever noticed that there are some weeks where your motivation runs high, you are killing your workouts, staying on track with your diet and feel like nothing can you stop you from achieving your goals? Then suddenly, like the flip of a light switch, your motivation drops to zero.
For whatever reason, it's so easy to go from 0 to 100 and back to 0 without any warning. Something messes up your schedule, a kid gets sick, you have a night out where you eat too much food or drink too many beers. Heck, sometimes for me all it takes is for the weather to change! We all have our reasons as to what causes motivation to shift, but it's what you do during those difficult times that's important.
When you go through these phases (and we ALL go through them), it is really important to remember what your long-term goals are, and focus on creating habits around those. For example, if you have a day where you don't feel like working out, but already have an established routine of going to the gym, maintain that same habit by just getting yourself to the gym. Even if you don't do your typical workout and just want to walk on the treadmill or use the elliptical and watch Netflix, you are still maintaining your habit and focusing on reaching your goals. If you know that you are fighting the mental battle of wanting to snack all weekend long, maintain your habit of having healthy, nutritious foods in the house, rather than going out and buying junk food. This way, even if you do end up snacking, you only have healthy food to choose from. And most likely, you will probably end up not even snacking on it.
These times of low motivation don't make you a failure or an unsuccessful person. It's a constant cycle that comes and goes, and eventually you will find your motivation again. Living in the 'all or nothing' mentality only sets yourself up for failure, because you can't live in the 'all' phase ALL the time. Expecting that of yourself leads to anger and frustration, which just makes it worse. Try living in the reality that yes, you are going to have bad days, weeks, maybe even months. But it won't last forever, and you will come back from it!