What's going on with my Dream Recall?

I finally decided to start a Dream Journal about 4 weeks ago, and for the first couple of weeks, I'd remember maybe a dream every two, three nights, and what I did remember was pretty hazy. Then, out of nowhere, I had a really vivid dream, in which I could remember all kinds of senses, conversations, things like that, and I was writing said dream for about 20 minutes after I woke up.

From this point forward, I was able to remember a dream most nights. This lasted for a week or so. One night, about a week ago, I woke up several times in the night, remembering a dream on most occasions, but being so exhausted that I couldn't bring myself to write in my Dream Journal. And yet I still remembered 4 dreams really clearly upon waking in the morning.

So, why is it that since that night last week, when I could clearly remember all those dreams, I've remembered nothing whatsoever? I'm doing everything the same as I had been (Relaxation techniques, telling myself I'd remember dreams, and so on) but nothing seems to work :(

This hapens a lot in your first lucid dream. Although i don't know why,

You and me both are in very similar situations. My dream recall is very poor these days and I have also experienced waking up and feeling tired and falling back asleep immediately, it's annoying.