The elephant in the room letter

Hello all,
I was hoping for some advice. I was dumped by my GF of 5 months. It was out-of-the-blue.
We were doing okay. Texted and/or talked several times per day. But, one day she went cold. No response. Then said she needed to talk to me. She wanted to do it on the phone but we were working so it took place via text. Because of her going cold, I knew it was a break-up. I am a insecure and may even be needy. I am addressing all this during NC.
I did not beg or anything. Just said that I was heartbroken and asked her why. She said it was someone else. Not sure if that was an actual excuse or a quick response to the question. I think it was moving too fast (even at 5 months).
My question is for those with the elephant in the room: Did you send a elephant in the room letter after NC and then wait a longer time to do a memory letter or did you combine them?
Any testimonies would be appreciated.