Stop caring so much what other people think. If somebody shuns you because you needed some time to yourself, they weren't someone whose opinion was valuable anyway. Or do care what they think, if that's valuable to you, but the point is that this is a choice you are making.

At the end of the day, only you can decide what your values are. But right now you're trying to have it both ways. You're trying to keep up with the people who go 100 km/hr and keep the good opinion of the people who value that above all else, and you're also trying to not actually go that hard. If somebody else is all-in on something and you're not, either because it's not important to you or because you have more balanced priorities, they're probably going to pass you. You can either be okay with that or not be okay with that, but you need to pick which one and act accordingly.

Once you've decided what your priorities are, there's plenty of more practical advice--for one, the day is probably more like 15 to 16 hours, not 12, plus things like time management, not procrastinating, scheduling your "you" time and your friends and family time just as seriously as you schedule something else, etc.. But all the scheduling and time management and lack of procrastination in the world won't help you if you don't know what you want.