Is my "best friend" gone for good? Was she ever a real friend?

I have well now I would say had a best friend for about 8 years we were unseperable, we did everything together we acted exatcly the same. she was the one i would always take everywhere with me and i would always go everywhere with her. it wasnt until highskool wen we seperated because she went to one school and i went to another. but we still kept our friendship strong like it always had been! it was hard for me to not be with my bff in the same school because she was my bestest friend, but we always would sleep over eachothers houses in the weekends, we never ween a week without seeing eachother. so okay just a few months ago i was able to go to the same school as her and i was soooo happy we both were becus it had been 2 yrs since we went to the same skool together. so just imagine being in the same school together once again? it was gona make our highskool years much better than we thought! until about a month after i had enrolled at her skool she got a boyfriend and thats wen it all changed, she stopped hanging out with me and only hung out with him, i never thought my bff wud do that, it was so surreal to me becus i just didnt think that shed be capable of that, it was so easy for her to just forget about me, i would always bring it up to her and tell her how much i missed our friendship, i would cry in the hopes dat it will one day be how it was b4. so 4 months later they broke up and i was there for her, despite what she had done to me. it was summer and i thought wow now shes single so we will hang out a lot like usually do during our summers like bff do. but to m surprise i was wrong, out of no where she started hanging out a lot with one of our mutual friends and thats wen i knew i lost my friend, its been 2 weeks since theyve been hanging out a lot and theyre even calling eachother "best friends". thats wen i knew i had lost my friend forreal. this whole time i thought her former boyfriend was the problem but turns out the problem is her. I feel like crap becus what did i do? i was always a great friend, i cried for our friendship i basically begged her to try to make this friendship how it was before but nothing seemed to work, i gave it my all. and to be honest i am exhausted. i just want some feedback, was she ever a true friend? am i exaggerating? shud i keep trying? pleaase help me.