If you can only keep it up for a week then the changes that you are making are some combination of too many and too drastic. Other posters have already given you some good suggestions about starting from where you are and making small changes, one or two, at a time to get where you want to be. Because you have to remember that what you fall back to is what you have deemed the best option, so it's going to take some time and effort to make each change you want the best option for your resources.
Well, since my "goal" is a healthy-enough-for-me lifestyle that makes me happy, I don't really have any lines drawn of "on track" or not.
I'd suggest that you use a "gung-ho" week or two to just eat and move how you "normally" do, with no attempt to restrain or be healthier, but track every choice along with notes on how you feel, how hungry you are and when, how satisfied / full you are and for how long, what your emotional state is when you are making food or movement choices, how stiff / bloated / sore your body is feeling, how well you are sleeping, etc. This is your baseline data, which will give you a better idea of what your favourite foods are (since you have them often), what your normal schedule is, what types of foods you find more or less satisfying, how much movement and sleep are normal for you, etc.
While you're at it, check out a calculator to get an idea of what calorie range would be right for maintaining your body at around the middle of the "healthy" BMI scale. I like this one for BMI: www.health-calc.com/body-composition/bmi-a dults and you can use your baseline data for a "normal" day of movement to figure out mid-range of calories for maintenance here: www.health-calc.com/diet/energy-expenditur e-advanced You take the calories indicated and then minus 200 for the bottom of your maintenance range and plus 150 for the top (so, 1832 calories needed means a range of 1632 to 1972).
So - now we've reached the end of your "gung ho" period and you're losing focus. That's okay, because the real "work" is over since you have some solid information about YOU. Hopefully you've now gotten in to the habit of tracking, so it doesn't seem too hard, and you might even try changing over to using the tracker more as a planner --- where you can put together a rough plan for a week so that grocery shopping is easier and you can do some bulk prep and know your timing for pulling stuff out of the freezer (which will overall save you time, money, and stress). Either way - don't try to be strict or restrictive, and give yourself room to adjust to your mood and last-minute bits of life! Oh - and don't try to go below your calculated "healthy maintenance" range. Instead, make small changes and see if your intake naturally falls to sit within that range over time.
At this point, take a look at your data, see where you are lacking in nutrition or activity, and pick just one change that you could make that you would ENJOY and that would make your lifestyle a bit healthier than it was. Some ideas: ADD a glass of water before every meal, or ADD a serving of vegetables to every meal, or ADD a 10 minute yoga stretch routine before bed every day. Whatever you choose to try, make sure that it is easy to fit in, be experimental with it (try different types, different preparations, different videos - whatever), and make sure that it is a change that you really enjoy. If it isn't that enjoyable, keep tweaking it to see how you can make it better.
Once you've got one new thing happily fitting in, then choose another change and work with that. Some ideas: start having an appetizer salad or broth soup or high-fibre crackers with a hot drink before every dinner, add in a late-evening stroll with your partner or before-dinner stroll with your kids, add in yet another serving of vegetables or fruits with each snack. Again, make sure that you enjoy the change and that it feels comfortable as your "new normal" --- and then choose your next change.
As you keep making healthier choices, and keep finding new food and activity options that you really enjoy, you should find that your intake naturally goes down to your "healthy maintenance range" and that your exercise burn naturally goes up. Keep an eye on trends over time (weeks and months, not hours or days) and let your body gradually work itself towards being a healthier weight and body fat level - while you gradually create your healthier new normal.
When you focus on adding in new foods and activities that make you happy, then it becomes more of a fun experiment and not an overwhelming amount of "work" that needs "motivation" to stick with. Choices that make you happier are the choices that you stick with, so take your time and play around with options and HAVE FUN!
The best part is that there is no time limits and no rush --- you and your body have taken your whole life to get where you are, and you have all the rest of your life to gradually make changes to keep being healthier and happier.
Sir Terry Pratchett: "Science is not about building a body of known 'facts'. It is a method for asking awkward questions and subjecting them to a reality-check, thus avoiding the human tendency to believe whatever makes us feel good."