Life is hard. Have you noticed that whatever stage you are in life, what you experienced in the past has that patina of "easier"?
Here's my theory: Life is hard because we don't like to make choices -- we want to have it all.
This can be observed with anyone trying to develop their career, grow their family, have a fulfilling social life, and be a respectable citizen -- that is a lot to do and most of us (dare I say all of us?) can't make it all happen day to day. We have to make choices about what is important to focus on each day, through the course of the year, and over our life time.
My other theory is that no matter what your life looks like, it would still feel hard. If you could jettison all the money concerns, work concerns, family concerns and plant yourself on a beach somewhere (my personal fantasy) with a servant bringing you drinks and preparing your meals, you would still have to make choices. Because they are only choices you have, they will seem hard. Really, think about it! If you're choices in life were limited to margarita, strawberry daqs, or which kind of beer do you want -- you would still agonize over which one would be better. (think I'm crazy? Have you seen Real Housewives of Anywhere or any other reality show? The stuff they worry about it INSANE sometimes!)
My point is: no matter how you think your life "should" be or what you "should" be able to accomplish, Life is going to get in your way. Don't be surprised or let yourself get discouraged. Life is hard and there will always be choices to be made. The upside is that you can pick which ones you need to make:
Should I bypass the second piece of cheesecake?
How hungry am I? And what am I hungry for?
Should I start dieting again or go on meds to control my pre-diabetes??