Edit; removed redundant quote.Hi , welcome to the UM , i think that maybe you are experiencing one of 2 things or perhaps both 2,
1.
maybe he is very lonely and miss you , maybe he is trying to be with you, he comitted suicide so heis soul must be in real pain , maybe he is still traped in this world unable to go to heaven or hell and when that happens spirits are supousdly very very lonley , or maybe you miss him so badly that you just dont let him go to the other world.
2.
Maybe you miss him so badly that your mind creat flashes, images of him that really arent there , maybe its just that you miss him and wish to see him again , sometimes the mind can create a lot of diferent types of illusions , that didnt mean that you are crazy just that you have to accept that fact that he is gone and go on with your life, sometimes we think that we just cant stop thinking and crying for those who die because we feel that if we do, we will stop careing about them or that we are betraying the love we felt for that person but thats a mistake, is not easy but is necesary, when my father died almost 2 years ago i felt that was a pain that will never end, i just couldnt imagine me without crying and wanting to bring him back to life, but later i understood that love is more than that, you can remember him every day and keep loving him, thats all right , but maybe you are not willing to let him go , maybe a psycologist will help you , not a psyquiatrist , a psycologist, this things take time but can be solved.
i dont think you are crazy.