Hello !
I've had my first shared dream with my Twin Flame too, two days ago. Just a small precision we're in separation and not talking at the moment (Everything in my life for the last 4 months make me feel separation is almost over). Except when I woke up I felt nourished by the love we share. Every journey is different !
As it's been said, you should try to learn what you want that dream to mean, and most importantly, why now ? Really, you're the only one who can tell !
And about not being able to stop thinking about her, well she's your Twin Flame, that part is totally normal. And don't be disappointed ! Be happy it happened