In my experience, junior year of high school was the most stressful by far. Not only do the course loads start piling up, but a lot of change can happen in your life as you get closer to graduation. Coincidentally, that's also when my problems with procrastination and lack of motivation/energy started showing up.
I had been pretty good with time management and planning ahead up until that point. However, as the year trekked on, I developed a habit of being up late at night the day before an assignment was due. I always got things done on time because I feared for the maintenance of my grades, but regularly getting insufficient sleep was taking a toll on me. It didn't help myself at all while also being in school plays and the newspaper class which kept me on campus until late afternoon almost every day.
To make matters worse, these problems only worsened during the winter when the lovely Oregon weather kept the sun hidden away. There would be days where I felt fatigued and had a hard time doing anything. There would be nights where completing an assignment took forever because I kept falling asleep with how tired I was. There would be mornings that I had to scramble to get ready because I woke up late after going through that process.
As the problems continued into my first year of college, I decided that enough was enough. I started seeing a therapist through the counseling center at my university. I discovered how nice it is to be able to vent about a variety of things to a neutral listener who could then offer you advice, resources, and analysis on the problems and its effects.
I stopped going when summer vacation hit because I figured being with my family, not having schoolwork to burn me out, and the shining sun wouldn't cause problems. I was right, but I endured a lot of stress and emotional pain in the following months as a result of brand new issues; that's when I realized it was definitely time to start regularly scheduling appointments again. I still have problems to deal with even while going to therapy, but it's comforting to know that I have a designated space to talk about them with a person who can help me make connections, provide insight, and encourage me to talk/open up at my own pace.
Each session can be different. Sometimes I have a lot of stuff to talk about because the past few weeks were rough, and other times I let my therapist lead the discussion because I'm feeling pretty happy at the moment and don't have a lot of talking points I specifically wanted to bring up. One of the most important things to remember is that progress is not linear. You can go up, you can go down, you can go side to side, do a loop-de-loop, and more. Depending on what you're dealing with, the problem may not ever entirely go away, but going to therapy can help you learn how to work with it and live your best life anyway.
Another important thing to remember is that there are no mental health criteria that need to be met before you can start seeing a therapist. The stigma says that only people with depression and other mental illnesses go, but even the happiest, most neurotypical person can receive incredible benefits from seeing a licensed professional.
I know that therapy can get expensive super quick and insurance can provide its own set of problems, but I strongly recommend at least trying it out for yourself if you have the financial means to. Your mental health is just as important as your physical health.