absolutely! i myself have done that and everyone i know that has lost a loved one has done that. nothing out of the norm, when you lose a loved one it takes a very long time to adjust to the fact that you can no longer call.
I would constantly call my grandfather's cell phone just so I could hear his voice on the voicemail. I would talk to him as his recording was going, I would do this several times because all I wanted to hear was his voice.