I know exactly the thoughts of "Maybe this is just a joke, and she will reappear one day soon." I am so sorry that you have lost your dear friend and even more so that it was by suicide. I have learnt some stuff since I lost my brother in 2019, some of it here on this forum, and that is that mourning a death from suicide is very different than feeling the loss of someone to a death that is "acceptable". What I mean is that if your friend had of passed through a heart attack or road trauma or cancer you have answers, you have the sum of 1 + 1= 2, it all adds up and while you are still in pain and suffer sadness, it is acceptable. I have found that mostly when someone dies by suicide it is "unacceptable". We have trouble understanding, we blame ourselves, we are confused and as you said, in total disbelief. The person may not have left a note, so you make up story after story in your brain as to why, even if they did leave a note, there is still room for so many unanswered questions. The sum is kind of like 4824 x 963 (a + b) = what the hell.
I am so proud of you for opening up to us and to come to chat and to let us know how tough this has been for you. It is tough, it is so tough but I wanted to also say that with the right support there is the chance for peace. Peace for your thoughts and peace for the feelings. They say time also heals all wounds, I don't find that to be true, I think in time we learn to live with the wounds and acknowledge the days that are heavier than others and to take comfort in the days that feel ok.
A few months is not very much time so please do not feel like you "should" be doing better or "should" be feeling differently. Grief is a very personal journey and it takes as long as it takes. So be kind to you, let the days that it hurts happen and also allow yourself to have good days too, there is no guilt in being able to remember your friend and laugh, or to have a smile, this is what she would have wanted for you, don't you think?
Part of my recovery was to engage with a counsellor who specialized in grief from suicide. I also credit talking to the wonderful community here, even after two years I have still not left! I also engaged in some hypno therapy, once again, not for everyone but it was the trick for me.
The feeling of being lost is also one I felt too, let us pass you a compass and help you on your way to feeling better.
Hugs to you Bee1998 and I am so sorry you have lost your dear friend.