I am very sorry for your loss. I lost my twin brother in 2001. He was 35 years old. I must say for at least 5 years I was in constant pain. I ended up suffering from depression and didn't realize what was happening to me until. When my life got very difficult, I even attempted to take my life twice. I was told I had Situational Depression.
Thankfully I was able to get the help I needed. Please reach out and try to find help. I promise you things can get better. Of course I still miss my twin, but I came out at the other end okay. He would want me to live a happy life. I know he would. I'm sure your brother would want the same for you. All the best to you.
Sincerely, Christine Ruiz
Also a "Twinless Twin"