What to do when you're basically told

That you were a rebound? Time has gone on since the breakup and you're getting on with your life but still think about him now and then because he meant a lot to you. But then hypothetically you're told that you were a rebound to him. It really stings because you were falling for him like mad and thought the feelings were reciprocated (as he said he loved you), how do you get over the fact you probably actually didn't mean anything to him? I know I sound stupid and I am focusing on other things in my life now, I won't make the mistake of going after someone who I even think for a second their not over their ex. But have you ever been told you're a rebound? How do you get over thinking that their feelings were never real? Sorry I just need some help 😓