i wouldnt call it a dry spell. A dry spell for me is when you dont get lucid for a long time. I would call this fluctuating dream recall... Its normal. Everything has influence on your sleep and on your dreamrecall. sometimes you are stressed or somewhere else with your thoughts or you drink or eat something that influences your sleep or your recall or maybe you get sick or something. even if you dont notice a direct change there might be something subtle. i had a time i was just a little sick nothing special but i drank a lot of herbal tee with a hell lot of ginger and it seem to influence my recall i had 3 or 4 nights in a row just very little fragments to nothing... i was wondering what happened because "i didnt do anything differently than before". as i noticed it and didnt drink the herbs before bedtime my recall came back within one or two nights.
Lucid Dreaming, dreamrecall and dreaming itself is a very dynamic and sometimes fragile process no night is like the one before.

I wouldnt think to much about it. dont get stressed about it. its natural and you might use some affirmation or mantra like " i will wake up after every dream and recall my dreams" this night before falling asleep to show your subc. that recall (still) is important for you.

hope i could help