a member

I feel like a backup or last option friend by my very own best friend. We've been friends since childhood and we're now both college students, I just want to say this now but I've noticed this long ago. I notice how she would only message me whenever she has problems or needs anything from me and honestly I'm a little sad. Ok tbh I'm jealous of her new friends now, she calls everyone her best friend I thought a best friend is only 1 person or at least for me. She'd tell me things like "you're the only one I've told about this, it'll be our secret" but I'll eventually find out that she also tells that to her other friends, I feel betrayed (idk). She also always posts different people (she has a lot of friends, very friendly to others) but her older post about just the 2 of us would be deleted....We didn't fight or anything like that. I feel stupid to feel happy whenever we hangout but I find that the reason she wants it is because she fought with her other friends, that would be the time that she'll tell me I'm her best friend but tbh it felt fake. Tho I think I don't want our friendship to end but also there's this part of me that's tired of her... I'm just stupid.