Loneliness Support Group
Loneliness is an emotional state in which a person experiences a powerful feeling of emptiness and isolation. Loneliness is more than the feeling of wanting company or wanting to do something with another person. Loneliness is a feeling of being cut off, disconnected and alienated from other people. The lonely person may find it difficult or even impossible to have any...

Grieving is a slow process, it takes its time. Your big consolation is that you were a good daughter to her, and gave her all your love. That is why she is at peace now.
I too went through periods of guilt, but I eventually realised that we can only do so much and no more. When the time comes, we have to let go. It is an end to suffering, and she is in a better place.
If you want to, you can join the Bereavement board here, where you will be able to share with many others going through the same experiences.
Hugs and good vibes.
You aren't alone... Your mom had the right to not want anymore intervention... She wanted to pass with dignity and you honoured her wishes... Bless you for that... You let her know that if it was her time then you wouldn't force her to endure anymore suffering... That was a gift you gave her out of love
You are feeling grief and it's hard to bear... Grief therapy can be helpful to try and sort out what you're going through or talking with someone in clergy if you have a faith
It's a process though and it will take some time... Big hug for you and a blessing...xo
Bereavement Group
http://www.dailystrength.org/c/Bereavement/support-group
Survivor's guilt
http://www.giftfromwithin.org/html/Guilt-Following-Traumatic-Events.html