Hi, I am so sorry for your great loss, I lost my dad Nov.26, 2002, I miss him so much still, some days it isn't bad, my brother and I call each other on the phone sometimes we laugh about some of dad's old sayings, and then we talk about how still, our hearts break.
There are really no words that another can say to bring much comfort, but many of us can relate to this through the loss of our loved ones, and even our pets.
There have been days since I lost my dad, that it cuts my heart as if it had just happened that very day, then other days I fondly remember him, and hope some day we shall meet again . . .
Your feelings are very normal, there are no deadlines on when or when not to grieve, do not let anyone say, "oh you have to get over this", my mom being so callous (had bad marriage) hurt my brothers and me when 2 weeks after we buried dad, she said that "us kids must get over this", could you imagine? Well, I will not rag on about that, but some people lack compassion, or some just very ignorant.
There are various stages of grieveing and not all have to be in the same order, these emotions by many are unavoidable and perfectly normal, I was reassured by my pdoc and therapist that I was not feeling in anyway abnormal in regards to my saddness. It is if a person feel suicidal after losing someone dear to them, then that is something to consult with a mental health professional
about such feelings.
Some people experience emotions such as denial, anger, guilt, saddness, not everyone feels all or some of these emotions, but they are very real. I have read different things on this mental process, and have found them useful in convincing myself I am normal, cause there are points that some of us feel like we are losing our minds or however one may like to put it.
Please feel free to come to our forums, there are many wonderful people that are so supportive in many ways
Grieving is different to many, I think having so many years spent together (not that time is key) sharing times, good and bad. . . the memories, like photographs in our minds make losing someone (at least for me) more difficult, but I think this is something universal and memories sometimes can bring one comfort, mine do and then sometimes they make me cry, knowing that dad isn't here with us.
Please take care of yourself, even seek counseling if you feel you'd like to, there is nothing wrong with that, it can help.

Sincerely,
DE

Sorry for this long reply