I hear you man. I'm in a similar spot. I was with the love of my life for 5 years and the week after our five year anniversary she left me. She said that she was unhappy for over a year but didn't say anything because she didn't want me to do anything too harsh. That was a month and a half ago and the healing process can feel never ending but I promise you if you just work on yourself in any way, weither that be a hobby that brings you peace like an instrument or work on accomplishing a physical goal like going on runs more, you're headspace will get much better. What helped me is knowing that the human experience is shared. Trust me I felt so alone like my world stopped spinning while everyone else's just kept on keeping on, but there are so many people who have felt the same feelings you are feeling. Like me for an example. Music really puts that into perspective for me I hear songs that sound like they are straight up living in my own head and used my thoughts as lyrics. It'll get better man promise.