I had to put my cat to sleep 7 weeks ago and I thought I was over i, but its starting to come back.?

I had to put my bombay cat Jack to sleep seven weeks ago. He was 12 and I loved him more than I had loved any animal my family had ever had ( probably because he was mine alone). He was very affectionate and loving. After he died I felt terrible for about 2 weeks and then the pain started to go away, but now its coming back and I can't stop thinking about him. Is there a way I can get over this? Should I get a new kitten? If I did no matter how cute and loveable they would never replace Jack.