It sounds like OP is in their first year, and likely first semester, of a college math program. One's first year in college has traditionally been a very large changeover point. College courses (good ones, at least) require a lot more study, rigor, and precision in writing -- especially in fields like math and computing. Admittedly, they're not for everyone. Furthermore, college life and courses require that the student take control of their own goals and become self-directed and reasonably disciplined without as much hand-holding or safety net supports from family or instructors. The combination of new challenges can be burdensome for many or most people.
For your program, also bear in mind that the discrete math/discrete structures course is generally used as a "transition" and introduction-to-proof course, which is the gateway to the rest of the studies in the math discipline. This switch from calculation-based to proof-based courses is therefore a third big hurdle that you're facing right now. The calculus II course shouldn't be difficult for a math major, exactly, but it's not the most important thing. In the far future it's possible that you may use little to none of that content; but the concepts of logic and how to read and write a proof are essential skills used always by any math practitioner. Do you like the discrete math content, does it fire your imagination? That's the best sign that the math major is the right choice (and that's what most later classes look like).
For the math courses, I would encourage you to start learning to read the textbook itself. One of the most formative experiences I had was, in my first college calculus course, realizing that the classroom experience itself wasn't doing much for me (delivered at distance via closed-circuit television), and I started reading the book very carefully and slowly on my own. The fact that I could do this was a revelation and was the primary tool I relied on to get through an undergraduate math program. Arguably, my job today is basically to apply that same skill: read an arbitrary textbook and summarize it in digestible chunks for current students.
For time-management skills, I recommend that you read the first 3 chapters of Eva Lantsoght, The A-Z of the PhD Trajectory. You're not going for a PhD (now), and neither am I, but recently I've found the time-management procedures there to be extremely helpful. Lantsoght says she developed most of them while she was flailing as an undergraduate science student.
More generally, I would encourage you to use your undergraduate experience (esp. the early part) to take courses from as wide an array of disciplines and departments as possible, and see if any open your mind in ways you didn't expect. You likely at least have general-education requirements, and you should look at these as opportunities and essential college experiences. Do any of the areas excite and intrigue you more than mathematics? Possibly areas you'd never even heard of before now (many of which don't exist in the high school curriculum)? If so, then you should follow the path of greatest excitement (balanced by considerations of resource and career potential). You can change paths any time in life, but it's certainly easiest at the point where you are right now. Early undergraduate years should be a time of broad exploration.