Leah,
So sorry to hear about the loss of your Mom and best friend. It must be very difficult for you. I recently lost my partner of more than 23 years and it really hurts. I don't know if I can help you out but I've read two good books on grieving, which helped me understand the stages of grieving and why we are experiencing such strong waves of emotions. Understanding the process may help you deal better with your grief. The books are as follows:
The Mourning Book by Helen Fitzerald
Don't Let Death Ruin Your Life by Jill Brooke
Also, the following websites provided some very good insights on the grieving process and I found them very helpful and comforting.
http://www.helpguide.org/mental/grief_loss.htm
http://www.acponline.org/public/h_care/10-griev.htm
http://home.att.net/~velvet-hammer/grief.html
I've also been keeping a journal almost daily about how I feel. I write everything down, all my emotions, joy, anger, sadness and pain. For some reason, writing it down gets it out of my system because I don't have anyone to talk to at home anymore and it's lonely. For me the grieving process started 18 months ago when my partner was diagnosed with inoperable lung cancer. Hope this helps.
Tom