You could look at life as an endless series of problems.
Why don't the cool kids like me? How will I get this girl's attention? What should I study? Why can't I find a more interesting job? Should I get kids? Wow, I love my kids, but taking care of them is exhausting. How come I'm already middle-aged, but I haven't achieved anything with my life yet?
And so on.
There's nothing wrong with having problems. Solving problems gives meaning to life. Life would, truly, be boring if we had no problems.
Sometimes we get stuck in a particular problem though. I have this right now. There's a problem I'm really, really struggling with, and I can't figure it out. It feels like a massive problem that will never go away.
History says otherwise, though. Almost every single problem I have ever encountered has gone away, or I've solved it. So, if I had to bet, I'll solve this problem too. I know it.
It just doesn't feel like I will.
In times like these, it helps to zoom out. I look at old journal entries, or at notes I took a few years ago. Wow, I was dealing with problems that seem trivial now. But at the time, those problems seemed to define my existence, just as my current problem consumes me now.
So when you feel stuck, zoom out a little. Or a lot. Getting some perspective probably won't solve your problem, but it will probably make you feel better.