Of course you do. At this time, it helps not one whit to know he's still with you, because he's not there to hug and pet and cuddle. Knowing we did the loving thing doesn't help, because our hearts are stronger, and the feelings come in a flood, intellectual understanding be damned.
I felt like my house was empty when Skippy died. I still had 2 dogs and another cat. They have such big personalities. They play such big roles in our lives. Grieve and cry, it's totally normal. It does get easier, but you will always miss him. Maybe someday you can give another cat a wonderful life.