I am very sorry for the loss of your mum. Please I request you to accept though painful, mum is gone for good,But she is safe for n the hands of God. It's healthy to be guilty and blame yourself.If you know that you had a strained relations, ask God to forgive you and also forgive yourself. Then give yourself time to mourn and please talk to your Pastor and say how you feel.Don't stay alone.Talk to a person you trust.Whereas we continue praying for you for God to walk with you especially at this time.Romans 8:23 says we believers also groan, even though we have the Holy Spirit within us as a foretaste of future glory,for we long for our bodies to be released from sin and suffering. We too wait with eager hope for the day when God will give us our full rights as his adopted children*including the new bodies He has promised us.(Life Application study Bible).I will continue praying for you because I have also gone through grief and mourning for My Dad, my Mum, and very recently (22September 2021) I lost my Firstborn beloved brother and it hasn't been easy but I have started healing.God be with you.Shalom