Hello popyang: Thank you for sharing your concern here on PC.
I see this is your first post. Welcome to Psych Central.
I'm sorry you are still struggling with the loss of your precious aunt.
I have to say your story reminded me of the death of my maternal grandmother & how I handled that. (As I recall I was around 18 at the time.) You were 16 when your aunt died. You handled your aunt's passing in the best way you knew how... & without a lot of support it sounds like. I think it's not at all unusual to have regrets at how we handled things in the past. (Hindsight, as they say, is 20/20.) Hopefully coming here to PC can be of some support as well as comfort as you continue to work toward putting your grief to rest.
Here's a link to a listing of articles, from Psych Central's archives, on the subject of grief & loss plus links to 2 articles on the subject of complicated grief. Also included is a link to the grief & loss quiz here on PC:
Coping with Grief | Psych Central
What is Complicated Grief?
Complicated Grief: How to Get Unstuck
Grief and Loss Quiz
Plus I thought I would also share with you my own personal favorite among the grief & loss articles in PC's archives. (Please be sure to read through to the end. That's where the gold is):
What My Dog Taught Me about Grief and Loss
I hope you find PC to be of benefit.