Shanghai or Hong Kong???

I’m having a hard time to decide if I should stay in Shanghai or go back to HK. I have been working in Shanghai for almost 5 years. This company is owned by my ex-bf’s mom but we broke up bout 6 months ago. We are still friends and he is also working for this company. I’ve found that it is hard to forget our past because I need to face to and work with him almost everyday. I have only very few friends here and I feel very lonely sometimes here by myself. Sometimes, I want to quit the job and go back to HK but sometimes I don’t because I’ve put my great efforts on this job. It is kind of pity to give it up. I was trying to meet some new friends in Shanghai but it wasn’t easy. What should I do? Do you gals have any good suggestion?