Should I even keep trying?

My friend and I had an argument. I apologized & nothing got fixed. Some days later, she sent me a letter saying that she didn’t want it to be the end of our friendship but at the end of it she said “GoodBye ___” now today, I asked her for help on hw & told her to go to the library with me. She grabbed lunch & I left. Waited the entire 30 minutes & she didn’t show up. When I was walking out, I saw her in the hallway & she said she “forgot”. Idek how she could forget in those 30 minutes. I’m a person. I’d understand if I had told her “hey, remember this subject for me & remind me later on” no. I literally told her, meet me up in the library after you’re done with your food so you can help me with hw. I’m not even mad about not getting help. I just hoped to talk things out with her in a more private place. The only time she tried talking to me was some days ago when I was walking away which might’ve looked like I was ignoring her but I wasn’t. This is my second attempt in talking to her.