Hi Sorrow, welcome to the forum!
Fadem gave some good advice on doing a RC when you wake up, this will give you lots of opportunities to become lucid! I also agree that what you described whas not a shared dream, but merely your subconscious popping up something you have been thinking of. This does not mean that SD isnt possible, only highly unlikely.
Let me add some general advice to this, if you fall asleep very fast you should definately try WBTB, combined with either WILD or MILD. I wrote a technique for the first, which you can find here, I think this one works particulary well the faster you fall asleep.
Good luck with your quest for LD’s! 
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