Sorry, TinyBear but "try harder" doesn't mean much. If you're going to succeed where you failed before, you're going to need two things:
First, a goal -- figure out what you can do consistently and make it realistic. And second, a plan -- to achieve that goal
At least that way if you fail you'll know why and by how much. Without that goal, you have no idea where you're going. Its like driving around in your car without having a destination. How will you know when you get to where you're going?
If it makes you feel any better I fail in my fitness goals for 2019 too. My "resolution" this year was to get under 10% body fat. A place I had been close to but never below before.
When I lost my gut the first time, after years of inactivity. I did it completely through diet and with no exercise whatsoever.
Thing is, I still have times. All I'll need to do is not eat anything for the rest of the year. Yeah, right. I know. But the point is to never give up while there's still have the opportunity to try.