my best friend

so my best friend goes to a different school than me. and she hangs out with this group of kids and she likes one of them. she wanted my to meet them so i did and they are all super nice and they became my friends too. so a couple days after i hung out with all of them, the guy my bsf likes, snapped me and told me he thinks i’m pretty, at that time i was talking to someone so i told him thanks and then that was just sorta the end of it. and so like 2 weeks later, he found out that i stopped talking to this kid and asked if i wanted to date. i told him no plus i could never do that to my bsf. he was ok with it but asked me to not tell her. so i said ok and never told her. now this week, my bsf was hanging out with them last night and i couldn’t go, she asked me why i never told her and that she’s really sad about it and now i’m afraid she hates me. i kept apologizing and she said it’s fine but i know that she isn’t ok. what should i do???? i told her that i turned him down and that i would never date him but i can’t lose her!!

PLEASE HELP??? i’ve been crying all weekend!