Drifting from the Person I care most about

I've come on here to let go of some emotions because my heart feels kind of heavy. I don't really like writing my feelings on the internet but I don't know what else to do. So, recently I feel like I'm kind of drifting from my best friend. I understand that they're busy and don't have much time to talk in general. I think that's the main problem. However, I see them making time after school to talk to other people. And I assume that my friend also texts other people often too. And whenever I see my friend talking to other people they seem more happy and recently, they've seemed kind of bored whenever I walked up to them. I tried to ask them a couple times if they're okay because I thought they seem a little different. But they said they are. I'm just really sad that I'm drifting from my only friend. But obviously I'm not going to say anything, because I've learned to keep some emotions to myself. Honestly, I've always felt alone no matter what. Even if I had 100 friends I'd prob still feel alone. But at this point I feel like I've drifted from everyone, even that one person I wanted to be friends with for my life. I don't care if i have no friends ever again. Just my best friend was enough for me. Idk, I hope it gets better but I cried a few times. I feel like my best friend now prefers talking to other people over me. I guess that's fine but I can't act like I'm not hurt. We had so many inside jokes and every second I spent talking to them, it made me feel better and got me through the worst of times. I even told my therapist and parents that talking to my friend made me the most happy. Talking to my friend is the ONLY thing that makes me happy tbh. Now I'm even scared to go up to them in the halls. A few times when I went up to my friend they went like "oh." So it makes me feel that they weren't expecting or wanting to see me today. I feel like I could disappear for the whole year and it wouldn't make a difference. I prob won't be coming to school for a couple of months starting in a few weeks so... We used to talk to each other how we got each other through quarantine and school. We used to joke about doing so much together. I hope it'll get better. No matter what I would do anything for my friend. Even when I was busy or sad I felt like I was there for them. I've made mistakes too because I'm not perfect but I'm trying my best. I've tried my best just to be alone... To my best friend: I know you will prob never see this. But thank you for everything. Honestly I'm 99% sure that we won't completely drift apart and I hope we can get back to where we were before. Honestly, idk if I'm just more depressed lately so that's why. It kind of had an impact on me when you said you'd want to go home right after school but then I'd see you hanging out with other people. I know it was never like this but I felt like you would rather talk to other people at this point. But thank you for everything. (this is just appreciation.) GIRL I hope I can be a better and more fun friend soon haha. I never told you this but I am always scared that we would drift or that you'd replace me. I didn't want to think about it because you mean SO much to me. I was super scared especially when we go into college that you'll mostly forget about me. Anyway, I'm done. I wish I could tell you this but I know you're busy and prob don't want to be burdened by this, it's not even a big deal tbh. I'm just sad. Anyways ily <3 and i'm sorry if I did anything wrong...

Update: I wrote this post a few days ago. I feel like it had gotten better because me and my friend facetimed and it felt like just usual times. Maybe I felt like my friend didn't like me for those few weeks. I hope it won't go back like that. Either way she used to say stuff like "you are my only real friend, you got me through quarintine and school" etc. But now I feel like those words aren't true anymore. Like she is friends with a LOT of people so I don't think that sentence was accurate in the first place. Especially those times where I would go up to her in the halls when she was hanging out with her friends and she said she would be leaving. It's fine if they aren't but I believed them at some point and I'm not so sure now. I wanted to text her a few times about something but I didn't think she would want to hear from me. Anyways, it's gotten better but the past week made me reflect over everything. I just wished I hadn't believed those many sentences because now I'm second guessing.