Am I in the wrong for beginning to question my relationship?

**TLDR:** I'm starting to feel overlooked in my relationship. Hi everyone, I'm a 23-year-old guy in a nearly three-year relationship with my partner, who is 25. We met during our undergraduate years, but shortly after we began dating, she graduated and entered law school. Over the years, our relationship has had its highs and lows, but recently, it's began to decline. A significant part of the issue seems to be her busy schedule—between law review, her clinic work, classes, and socializing with friends. I fully understand that law school demands a lot of effort, but I'm struggling to feel like I matter as much in her life. My partner is caring, thoughtful, and truly wonderful. She has apologized for the compromises I've had to make, which has helped a bit, but the situation is still weighing on me. There's a growing sense of resentment because I can’t shake the feeling that I’ll never be her top priority. For instance, about a year and a half ago, a classmate of hers confessed feelings for her. Although she turned him down and insists she's not interested, they've remained close friends. They've gone out to dinner several times, and he even helped her secure a job at the public defender’s office for next semester. It’s difficult for me to understand how she can stay friends with someone who has, on multiple occasions, suggested that she cheat on me. I try to hold back my feelings because I see the career benefits for her, but whenever I bring it up, she doesn’t seem to grasp why it bothers me. I know she’s a great person, but some of this is hard for me to accept as just part of our reality. The latest incident happened tonight—she canceled our plans to help a friend prepare for a trial. Earlier today, she informed me that our trip for our three-year anniversary is off because she’s signed up for a law school competition that weekend. Most of her reasons are legitimate, and I understand that law school is demanding; I also work long hours in public accounting, so I know what it’s like to juggle everything. But it’s beginning to feel like I’m being pushed out of her life. I feel conflicted because I don’t want to seem unsupportive—she’s working incredibly hard, and I admire that. Yet, I can't shake the feeling of being invisible, like I’m more of a best friend than a partner. I’m uncertain how to handle this situation, or if I’m being unreasonable. AITA for questioning my relationship?