1) Life is going throw some crazy things at you, remain as consistent as you can but do what keeps you sane. If you do not put an emphasis on your sanity then you are far more likely to fall off the wagon in the future. Not to mention if you're already stressed, adding stress to workout 5 times a week, trying to hit PR's, while also fixing all your meals from home during the week might not be in your best interest. This would be a great time to maybe move to 3 times one week and working on technique. Also it would be a great time to go back to your most successful eating habits rather than try to do it all. Then once you get rid of some stress, you'll be no worse off and ready to kill it.
2) Almost every injury can be worked around to some point. One of the most common issues people note for why they gained weight is that an injury stopped them from exercising. If you have low back pain then heavy squats might not always be a good idea but this could be a great time to work on grooving a great deadlift pattern for when you're back to full strength.
3) Using the best program you find on the internet might not be the best for you because it does not meet your needs. You're parents were right, you are unique and you should have a program that reflects that. Two people could have identical goals and similar builds but after an assessment come out with a totally different program. If one has a history of knee issues, sits at a desk all day, and can't get their hands over their head without using the low back...we might have to do things a little bit differently to reach their goals.
4) People cheat most exercises. The body picks the path of least resistance and if you do not focus on form you can lose valuable progress. Simple exercises like planks, dead bugs and bird dogs aren't so simple when you do them right. Rather than load up every exercise as much as you can try going slower and focusing on technique. In the video below I use a stability ball and make sure to exhale (like I am blowing out a hundred candle birthday cake) when my arm and leg are extended. These changes make the exercise much more fun.
5) Consistency is the most important component for almost any goal which is why it is kind of listed twice. You want to lose body fat? Consistently change habits that are holding you back (1 habit at a time). Want to gain muscle? Workout 4 times a week for 52 weeks. DON'T program hop every other week. Get a workout program that you like and do it for 12 weeks, then you can think about switching things up a bit. I used to want to get everyone to lift heavy but I discovered that not everyone found that enjoyable. So I learned to compromise and get them lifting heavier but using finisher circuits to help them get that tired feeling that they crave.
6) Change only one habit at a time. I see many people get super excited about exercising and trying this new diet made up of only cat food and apple cider vinegar (don't actually do that). Then after a couple of weeks that is too much and they fall off the wagon. Start out easy, even painfully easy, and make sure to complete each habit to the best of your abilities. Then as you start to see success, the changes can be a little more difficult each time. If you ever stumble, go back to some early habits and rebuild success. Don't get cocky and try to change everything at once, one habit at a time!