Harpfreak....I'm sending you white light to help comfort you now.
Having been through your situation myself - I know how you are feeling. People will say many things to you such as "Time heals", "He's in a better place/out of suffering etc"....but it doesn't stop the heart wrenching sadness that you feel.
Nurture yourself now - be kind to you. Make sure you nurture both body and soul. Eat well....meditate.
I'm pleased that Bob has visited you twice - he's most certainly aware of how you're feeling.
Two things to remember...he also has work to do over there and will sometimes "appear" to you, to be away. If your need is great he will be there with you. Remember we have our own guides there to steer us.
Secondly, try not to allow your grief to become so heavy that it puts a wall up that may not enable you ( or Bob) to communicate. Meditation will help with that.
Best Wishes in this part of your Journey through this Life,