I have also dealt with a lot of deaths in my family. Most recently my Mom (Aug. 2012), then 8 months later my brother in law. In 2007 my husband's youngest brother who was 21 at the time was killed in a tragic car accident. And my father in law then passed away in 2010. In between there I've also lost three pets (cats), which hurt just as badly.
The loss of all these people had different levels of grief for me, but I grieved non the less. My 21 year old brother in laws death was a shock which left me in a state of denial for a while, then I accepted it finally. When my husband and I got married he was our ring bearer, and for years he would spend the night at our house, we called him our adopted son. So, it was a big, big loss.
My father in laws death was sad and painful, but since he had been very ill with cancer his death put his suffering to rest so therefore it was easier for me to accept. He also lived a full life well into his eighties.
When my cat Baby was killed by getting struck by a car I was absolutely devastated. I could not peel myself off of the couch for a couple days.
My Mom's passing was by far the most, absolute worse grieving I had ever experienced in my life, emotionally as well as physically. As I said she passed in Aug.2012, I was the one who discovered her after she passed. I had the frame of mind to immediately call 911; was pulled into the other room when the paramedics were performing CPR. The total shock of finding my Mom deceased put my anxiety over the top. Upon finding her my heart rate shot up, I did not sleep for 4 days---don't know how, but I successfully made it through her funeral without ending up in the hospital (which I thought I might).
I was very depressed for weeks afterward; had trouble eating so I supplemented my meals with Ensure drinks (the 'weight gain' one). I managed to finally get on with a normal sleep pattern. The worst of my grieving lasted about three months. I would have bouts of crying and missing her so much I would feel like I was coming out of my skin. What made me feel better was knowing that my Mom would not have wanted me to be in such a sad state. I could just hear her saying, 'Oh, don't feel so bad, I'm ok'. These days I'm at peace with her passing, and my grief has subsided.
Everyone grieves differently, and I've read that a person may think they are finished grieving and then go through it all over again---that is what happened to me. But that is just the process of grieving, it is what it is.
If you feel it has depressed you to a point where you find it hard to function daily, such as, get out of bed, eat, work, my advice would be to seek professional help. But if you think you are going through the normal motions of grief if you can just hang in there it does get better.
Best of luck to you! :)