Best friend as a teen and i live like exes still in love

female 20
me and S who was my best friend as a teen are very much on weird terms. I loved her with all my heart, like my own sister and so did she. We attended the same school. I however, failed 11th grade due to a prolonged illness and due to the tough guidelines of our school I had to either repeat an year or leave the school. I left it but my best friend was a part of my heart that I left there. Our houses are like miles apart so the only contact I could make with her was via phone and that was also very scarce as I didn't have a phone of my own back then because I broke mine. Failing 11th grade was a very traumatic experience for me because I have always been good at studies and been called brilliant all my life. For a very long time I refused to contact anyone or step out of house. I occasionally made telephone calls to my friend S but her mother hates me ( all of her friends actually because she's not even a decent human being, very superstitious and mean as well) so whenever I called her, her mother used to shout at her. I cannot take disrespect so I made my calls more occasional. S knew I loved her but eventually got other friends that she loved even more than me I guessed because she wasnt there for me when I was in shambles and going through my depressed period.
Years have passed my but we still have a bond. She has thoroughly apologised for not being there for me but I never let my grudge go. I was way too busy getting petty and jealous after her other friends and best friends that she posted about on fb. Where I could never give anyone her place, I learnt to let go of it and I didn't need a best friend I thought. Years have elapsed. But she's still there on social media dedicating me stuff at special dates when we first met or stuff. Why are we like scorned lovers? What the hell is this and what do I do with this friendship. It's like that girl is a part of my heart and I'm hers yk. We are both heartbroken but it has been years idk if I'm the same human now. The friendship can't be resuscitated I think. I'll always love her though.