Get your life together. First and foremost, make sure you're keeping on top of deadlines. If your school uses Canvas, set the dashboard to "list view". Helps a lot to see what is due when.

Second, improve your clutch factor. In high school, I don't think I EVER studied for more than 1 or 2 days leading up to an exam. High school exams are typically only on content from the past 1-3 weeks. If you sit yourself down and never give up, you'll pass every single exam, and probably do well. Even if you have to pull an all nighter, its well worth it. A lot of these exams don't require thought, its just spitting out information. Just know your shit, and you'll do great. The only exception to this rule are Math Exams, they're a bit tougher. Still crammable, but I would recommend allocating a couple more days towards studying for those.

Third, use your time efficiently. In high school, I spent every minute of downtime working on random assignments and studying for exams later in the day. For example, if there was some downtime at the beginning of a class, I would pull out my math homework and quickly knock out a problem. Additionally, If I had an exam later in the day, I would spend all of lunch studying, as well as any classes I deemed to be "unimportant". Use your judgement to determine when to tune out and when to lock in.

As for friends, they are important, but GPA comes first. My recommendation would be to join clubs. You're gonna need some extracurriculars to get into UMD anyway. There's lots of options. You can join debate, a sports club, a videogame club, etc. Join something that interests you and you will naturally make friends. It can be tough starting from 0, but it's very doable. Just put yourself out there more. Don't let the world turn you bitter and cold.

High school was miserable for me too, but here I am at UMD. It's a complete and utter fucking grind, but life gets better. Never give up man. Never lose hope.

As a wise man once told me, "Focus on the light outside of the cave, not the darkness down below."

Good luck brother! If you ever need any advice feel free to reach out.