Letdown going away??

My little guy is a little over three months old, and I've begun to notice that I don't have a letdown with every feed anymore. They were so noticeable until now that it's making me a little worried. Does that sensation just go away or is it me just getting used to it? I also just started my period for the first time since baby and I've heard that that can cause a slight dip in supply. Any thoughts? Or am I just losing my mind?! 😊