Probably overthinking but would appreciate help.

So there's something that has been bothering me for a while now. Me(20m) and my ex gf(18f), we both had sex for the first time a few months back. And you know how your first sex is, brief ,experimental and full of trials and errors. Wasn't that enjoyable so to say. So um,.. a few weeks later we had this conversation which was intended to be funny when she said, your penis is kinda thin and you should probably eat pills they advertise on porn websites. I want a thick dick. hahaha .. Well I think it's stupid, but the thing she said has been on mind lately. And it's bothering me so much. I feel like I've lost all my confidence. p.s – I've an average sized penis. And also we don't talk anymore.