You Are Actually Grieving
I gave myself a bit of a hard time for not moving on right away. It took me a few months to even feel like myself again. An advocate of therapy, I stopped in to see my therapist after I realized that it was taking me a bit too long to get out of the lows. She explained to me that I was actually grieving — it's not just for actual death, it's for loss, period. After that, we were able to pinpoint what part of the cycle I was on and what to expect.
She also reminded me to be gentle with myself. Everyone moves on in their own time, and the amount of time we spent together (which was a decent amount of time) is not necessarily correlative with the strength of the feelings. I needed to give myself a break.