@gulf coast girl
My deepest sympathies on the loss of your best friend - the other half that made a part of you who you are.
If you're comfortable with this, try "speaking" to her while cooking or going about other chores - speak to her spirit - just casually. Start with, "You know, _____, I really miss you so much and I'm really angry that you're not here any more," and take it from there. Or, perhaps writing down such thoughts in a journal will help.
In any case, it will take some time. Remember all the good times, laughs and highlights of so many years of friendship. You have a wealth of them, which makes you "rich" in many ways.
(Wish I knew your address, for I'd send you a grieving shawl Monday.)
Will be thinking about you and keeping you in my prayers.
~Rebecca