It sounds like maybe you would benefit from a stricter routine. At least, I know I tend to flounder when I am just let loose without many rules. If I have to figure out what to do every day and each day is different, I get totally off track with stuff. But when I get into a routine, it's way easier. I haven't gotten off track yet simply by virtue of not being able to eat very much right now, but I know that establishing habits and routines is the most important thing for me to do before I get to the point where I could.
Here are some suggestions, just in case they help!
Put your full week's worth of vitamins in a weekly pill case (I use this one: https://www.amazon.com/gp/product/B0C6XZN1YH). It's especially helpful if you get the kind where you can take the day's box with you for those later in the day doses like calcium.
Make the same thing for breakfast and lunch every day, or have a rotation of things you can do that are all close to the same in protein value. Plan a dozen dinners that are also roughly the same in protein. Add them up and make sure any breakfast, lunch, and dinner chosen from your repertoire will hit your protein goal. If not, plan for a snack or two in the same way.
Don't eat things that are not nutrient dense, and if you do have a treat on occasion, make sure you're limiting yourself to once a month, not once a day! (And if you happen to love chocolate, consider this for one of your daily calcium supplements: https://procarenow.com/products/calcium-dark-chocolate-500mg-calcium-500-iu-vitamin-d)
Consider getting something like the Portion Perfection plates and meal prep containers if you struggle with portion size
Buy a bariatric cookbook to help with food choices and portions
Put your gym or exercise time on your calendar and treat it like you would a doctor's appointment (I struggle with this so much)
Or, if you hate the gym, choose exercises you'll actually look forward to. Going to a gym is not a requirement but moving your body is.
Put all your reminders for vitamins, mealtime, snack time, and exercise time in your phone so you get reminders