You have been under a lot of stress for a long time so you're feelings aren't straightforward and I don't think there is a 'proper' or 'correct' way to feel. I was quite 'relieved' when my mum died because she had been suffering for 9 months with cancer. Looking back, I suppose I was relieved she wasn't ill anymore, I definitely wasn't relieved she was dead.
The most important thig now is to be good to yourself. Have you got family and friends to help you?
My mum has had cancer the last 2 years very advanced on initial diagnosis I feel I have been grieving for my mother the last 2 years and the sense of relief since she died has been overwhelming. I would have rang her 2/3 times a day and called in most days. I have 3 dc and work full time in a busy fast paced competitive job. Should I be more upset? Am I just going to collapse with grief soon. What's going on why am I not more sad?? I'm feeling ...guilty