My heart is with you. Its so hard to lose your best friend. Anyone close to you for that matter.
Yes its normal.
Do something for her if you can . plant a tree , let balloons go. Collect for a heart group in her name.
Shes there, shes in heaven watching over you. Keep on crying that is normal.
Best friends are hard to come by. When you lose them...its hard.
My prayers are with you....