Is it normal to not feel any pleasure while grieving?

We just experienced a death recently and it's really torn me apart to the points where sometimes I just sit there for extended periods of time and do nothing but feel the aching in my heart. More importantly, it's started to affect my sleep.

Usually, I masturbate to help me get to sleep when i'm stressed or just too awake, but recently it's almost as if those pleasure sensors are completely turned off. No enjoyment from it what-so-ever, and it's not like I feel guilty for doing it or anything. It's just . . . well, not feeling it. Then i'm left laying there with all this sadness when I would like to escape to dreamland and give myself a break, not to mention the messed up sleep schedule.

is it normal for this to happen?