Possible ?

This is something I didn't think was possible but I've been hearing a lot of stories lately from friends and online (both personal and "he said she said" stories) that it's possible to bleed as though you're having a normal period after conception. I'm only 19, pretty new to everything sex Ed/ pregnancy related. I always thought that if you're pregnant you don't have a cycle Except for the occasional spotting , so if anyone with more experience/knowledge can help explain what I'm hearing that'd be nice lol :)