has my bff moved on?:(

i feel like she has because we started to be friends in year 7 to year 11 and we have had some ups and downs but i was able to still be friends with her
but there's something that i noticed she knew ppl in school or outside of school and i saw her and felt replaced
from secondary school we both moved to college and at first she was happy to know that i was there, but still had new friends she would sit with others
my mental health wasn't great and as it would distract others, in class i had to leave the college
and i didn't let her know but i feel it is my fault
i haven't seen her for so long but i saw her infront of my house with others but felt uncomfortable to say her name as she would find out where i live
and now she moved on to a different college and feel like i no longer talk to her