Not able to move on from a relationship even after 8 months

I (24M)have known her for like 10 years. She was my first serious crush. During school we were always good friends only but in between we lost contact due to section change and all. So cutting short we again came in contact and first became very good friends and then started LDR. We were in relationship for almost 1 year. Break up was from her side. Her reasons were vague and it was very visible that she just wants to end it at all cost and was not even trying to work it out for once. She then ghosted me. She has this pattern of going and coming back again but this time I am completely done.It's been 8 months and still there is no improvement in my mental health. I am keeping myself busy by reading books,going on a run daily but nothing works. I started behaving very weirdly like shouting at the top of my lungs out of nowhere, crying like a child and because of this my family is also worried about my. My concern is that earlier I was unemployed so I was at home only but now I am about to join a company in banglore on 23rd July. I don't want my mental state to exhaust me so much that I am not able to perform at job.

Please someone guide me from their personal experiences what should I do and just move on. I am don't want to think about her, her actions and blah blah related to her.i am done.😞