My boyfriend mentioned that he thinks I appear heavier.

I'm struggling to process what just happened. My boyfriend recently mentioned that he thinks I look "fat" — not in an angry way, just said it casually like it was nothing. But honestly, it feels like my whole world has turned upside down. I've always felt confident in my body, or at least I thought I did. Ever since he made that comment, I've found myself fixating on every little detail, doubting my appearance, and I can't even look in the mirror without feeling awful. It's as if that one remark has shattered all the positivity I had about myself. I know he didn't intend to hurt me, but it still stings. It feels like he sees me differently than I believed he did, and that's making me question everything. I just want to regain my self-esteem. Should I let this go, or do I need to talk to him about it? I don't want to overreact, but it's really weighing on me. How can I move past this without letting his comment undermine my confidence? I could use some advice... I’m not sure how to handle this.