Repeating dream that changes

So, every couple of weeks i will dream that i am working in a Decathlon (sports-wear shop) and the staff is always different, sometimes it will be my work friends, sometimes people from my college, and my goal is to get them out of the store as fast as possible, find a shotgun and then kill a Xenomorph (alien) that is somehow born in the toilet of the store. I dreamt this again yesterday night - this time i decided to just take the shotgun and kill the Alien before he was born, so i went into the toilet and shot what looked like the yellow part of an egg, after which i resumed my shift like nothing happened. But before that, a couple of weeks ago, i dreamt that the alien got out earlier and so he killed all the workers before i got him. Before that i dreamt that i got the workers out and managed to kill him with the shotgun. Before that it was me killing the alien in a different way - this time i stabbed him with a shovel. Before that it was the alien not appearing at all. Before that it was me killing the alien with a shotgun. And so on and so on. This has been happening for like a year now and with time i grew to realise i was dreaming inside the dream, but i don’t have any power to change the dream in any way and the alien always moves differently and has different strategies. Last night i told one of my staff buddies at work (in the dream) that i was dreaming and what happened, and he pinched me and then i woke up.

Does anybody know what this could mean or be?