Pop-up blocked

The other day as i was going through my daily non-routine activities, an interesting idea popped up in my head, then i said to myself, "hmmm, this would make a good article for my blog and i made a clear mental note to whip up something about it.
Hours passed by and when i was fully settled, i pulled out my tablet and all i could was to stare at the blank space, i tried but it seemed no matter how hard i tried my brain keeps coming up with a "ERROR 404: memory not found" sign. I sat there blinking very hard trying to juggle memories in my brain, searched but no results, i even went through my trash and spam memories, i searched and searched still nothing.
I was not going to give up without a fight, so i began pacing (cause i have seen a lot of people do that and come up with a big plan or remember something important...which i needed to do) back and forth processing every thought that had come into my head through out the day, ten minutes went by pacing, no results. thirty minutes, one hour, i would like to say two hours but there is no way am going keep pacing for more than one hour without result.
After all the pacing, my legs were aching really bad, i was having a banging headache, i was physically, psychologically, emotionally and "logically" tired when i decided to take a step back, breathe in and out, relax, let it go and then maybe it would come back to me.
It has been 3 weeks, it still hasn't come back.