There is nothing that anyone of us here can write to you that would assuage the pain of losing someone so dear. I'm terribly sorry for your loss and sincerely wish that you never had to face something as awful as this. I hope that you will show yourself compassion and take extra good care of yourself in the months to come. Have you looked into grief counselling and suicide bereavement support groups? Do you have people close to you who can help to support you during this time? If so please consider reaching out to them.
I have to echo @theguineapigking's advice on taking some time to allow your self to process the lost and reflect before taking a decision that, once executed, is irreversible. The pain you are feeling now is beyond describing and I cannot fault you for wanting an out to stop it. Like you, I lost the person I love the most to suicide not too long ago (and I am certain that he used SN to kill himself). I'm not the best at one-on-one conversations, but if ever you want to talk about it--or anything at all really, because a distraction can be a gift during these times--you're more than welcome to message me.
Please do be gentle with yourself.