so I'm having a problem with a friend

So me and my best friend use to be so close then all the sudden we stopped hanging out like we used to and she now has like a "group" of friends that's she hangings outnwith alll the time and sure I get it she has other friends to but she always puts them before me and it's so upsetting to me and I always have to text her and make plans ext. it's just so upsetting to me and I haven't been to her house since like September and I don't know what I feel like she has cut me out of her life and doesn't put any effort into out 6+ year friend ship so idk if I should keep trying or just let it go.