I still write in my dream journal even on the days I don’t recall any dreams because I like to take notes so I can try to improve my recall. For example, if I know that I dreamt but just can’t grasp the memories, I’ll write exactly that. Or if I have zero memory, I’ll write that down too. I even write down when I had a memory but was too lazy to sit up and write it down and consequently forgot it in the hopes that I won’t make that mistake again. 
I also keep track of my bedtime and waking time each night to see if the length of my slumber affects my ability to recall my dreams.
Don’t despair over your lack of recall; I recently went almost two weeks with zero recall, I’ve only ever had one low-level LD, still can’t recall a minimum of one dream per night, and I’ve been keeping my DJ for about five months now.
If you need advice on remembering your dreams, check out The BIG Remembering Dreams Topic - Part 2: [The BIG Remembering Dreams Topic - Part II)
Part 1 is here:
https://community.ld4all.com/t/the-big-remembering-dreams-topic/7050
There are many people (myself included) who have posted similar topics:
https://community.ld4all.com/t/dream-recall-has-left-the-building/13007/5
https://community.ld4all.com/t/remember-your-dreams-a-technique-that-has-worked-for-me/13553
There is much more advice on the forum and it’s not too hard to find. Good luck!