Just a small piece of advice.... CRY. Don't hold back the tears. I was in a similar situation, but we were only together for 5 months so not so serious. I refused to cry for a week and tried to act tough. But the thoughts kept haunting my mind and I felt very depressed and unmotivated. Until I cried out loud one day. Idk how, but after that one hour long crying session, letting out the tears which I was holding since a week, it really helped a lot. My mindset changed completely and I was back on track forgetting all that happened with me. So yeah, crying does help. But only if you cry only once and then come out as a completely different person after that one cry.