Pia.....I send my sympathies to you,,,,I know the grieving of losing one's parent--I understand how deeply you are hurting. Anniversaries are hard, because the memories come to the surface. I think the first anniversary is the hardest of all.
Perhaps you can do something symbolic and special to honor him....like, maybe, go to church and say a prayer....or, some similar thing.....
It seems like you have a hole in your heart from the feeling of loss of significant people who have been in your life. It really does hit hard....and it requires that you must go through the necessary grieving process for all of them.... The grieving is the beginning of your eventual healing.
I am glad you were able to come here to tell us about it.
My heart goes out to you....
dandylion