You really, really don't need to worry about how you're grieving. You can't get it wrong. Grief is simply your reaction to your loss. Let's say that one more time. Grief is your reaction to your loss. What does that mean? 1. Grief is Your Reaction
It means that you don't need to give a fuck about what anyone else thinks about how you are grieving. Are they obsessed about your reaction to the last movie you saw? How about to your reaction last birthday? I know these are ridiculous questions, but what I'm trying to help you see is that grief is your personal reaction or response and no one else in the world will have that exact response because it's yours and yours alone. Grief is a ongoing and evolving personal experience not an event or a thing that is predictable or that someone can judge any more than they should judge your personal experience of the steak you ate last night.
DISCLAIMER: What grief isn't: hurting yourself or someone else, diving into your addiction or other maladaptive behaviors and isolating. You may want to do these because you are grieving, but that isn't your personal reaction to grief - that's what you want to do to numb your personal reaction to grief. The people who love you have a right to call you on these maladaptive behaviors because these behaviors are not grief, but a call for support. These behaviors mean that your internal resources for coping are are depleted and you are self-medicating. Grief also isn't unrelenting depression or overwhelming anxiety. If you are experiencing this, it is evidence that your internal resources for coping are depleted and you need outside help and support. So, do the right thing and get the help you need. I know it's hard, but you can do hard things. You deserve it and we need you.
2. Grief is Your Loss
You can't get grief wrong because it's your loss and nobody had the same relationship as you, so no one else can know the depth of what you lost. You had your own unique experience of him or her while he or she was still on the planet. Nobody else had that. You had your own jokes and your own stories. Let me give you an example, it's the Weasley family from the Harry Potter series (if you haven't read the books yet, STOP because there are spoilers).
When Fred died, his twin George would grieve him in his own unique way because he had a different relationship than any other sibling. His other brother Ron would grieve him differently than Ginny, the youngest daughter. Each of their relationships with Fred was different and precious in it's own way. Fred gave them each something unique that would be missed. There would be some overlap for sure, you know he made them all laugh and pulled pranks on them all at one time or another, but each of them shared private moments with him over the course of his life and that was unique. (I took Fred's death very hard myself. Not kidding. I took it the hardest in my family).
So, react how you react and grieve how you grieve. You're doing it exactly right. Have your grief experience and don't allow others to judge it (but don't forget about the disclaimer). The last thing you need on top of your grief is to deal with judgments about it. Oh, and don't forget the most judgmental one of all, YOU.