She did things that no other girl would do like turn up outside my work after I had a night shift at 7am with breakfast she made for me, she wrote me love letters, she never swore, she always treated everyone with respect, she's really intelligent and very pretty.
Wow. She really cared about you. And you really screwed up. I hope you don't do that again.
LDRs can be very hard. 90% of them do not work out because you actually need to see the person frequently to maintain that emotional bond. Next time, find a girl in town, even if it takes longer.
I know it feels like your world is ending, but your heart just needs time to fix itself. You'll find another person eventually, don't do it too soon though.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)