How long will it take to get over my crush?

There was this girl for who the past 6 months I would do everything with. We’d run the same blog together, go to events together and lead groups together- and I thought we really had something. For those 6 months, I would be telling one of my closest friends everything about her and he’d always tell me what to do next and other naive stuff like “how I’d ask her to grad”... and two weeks ago, this girl told me that she didn’t like me like that, but rather she liked my friend. Two days later they became a thing and now being with either of them isn’t the same- and I’m not the same. I feel at an all time low in terms of self-esteem, and the things I used to do seem meaningless. All the things I looked forward to literally shattered in a single day. I meant to go to the dance with her (which was yesterday) but I had left early because I couldn’t take watching them dance together in front of me (when they both know that I’m still putting myself together.) I’m truly happy for her (considering she was in an abusive relationship before), but I’m emotionally destroyed…. how long will it take for me to get over her? Also, I’m lucky to have her in my life but recently I’ve been distancing and avoiding her entirely, is this immature of me? And should I feel a bit of betrayal from my friends part? I try not to, because again if she is happy then I should be too, but I still occasionally feel this way….. Thanks everyone.

Tl.Dr. I never had a relationship with this girl I liked but I felt like we had a chance for 6 months. Two weeks ago one of my closest friends and her got together and I still feel miserable- how long will it take for me to get over it?