Hi destiny and welcome to beyond blue.
I am very sorry to hear of your loss. I can see the relationship was a special one for you both. The thoughts you are having I would natural given the length you were close friends. The other thing to remember is that everyone will have their own expression of grieving and will have its own length of time.
when making new friends you would likely compare them to what you had ... it would also depend on what you want from new relationship(s) - a new best friend? If so, again, the comparisons would be natural.
Do you have anyone that are able to talk about these thought you are having?
One thing that you could do in relation to your friend who passed away is to find some way to continue to the bond with them - perhaps photos, writing a letter, etc.
Finally, there is also the option of professional support if needed - someone that you can talk through the thoughts and feelings you are having and finding ways to move forwards, which does not mean forgetting the relationship you had, but something else.
Peace with you,