AIO husband said he was surprised how unfit I am

For context I (33F) am 4 months postpartum. I was carrying a very large IKEA bag full of washing up the stairs in one hand and the empty wicker washing basket in the other. Our stairs are spiral and are quite tricky when going round the corner. Babies also asleep so I was holding the bag and basket away from my body so it wouldn't hit against my legs and make a racket as I was going up.

Anyway my husband (33M) was behind me the whole 20 steps. I got up to the top and asked him to turn light on as I couldn't see and didn't want to bash the bag and make noise. He turned on the light but then said "fucking hell".

I immediately asked him what I'd done wrong. I wasn't sure why he'd swore. He absolutely refused to answer me. After about 10 mins of me badgering and him saying "I don't want to say why" "it doesn't matter", he eventually told me "I am just surprised you're out of breath just from going up the stairs".

Honestly I felt so so hurt. Yes I'm overweight after this baby. He knows I am really lacking in confidence. Also, hello, he'd just watched me carry shit loads of washing up the stairs at a very awkward angle from my body, so I was just using arm strength. I didn't feel out of breath at all but I must have been breathing heavily.

I tried to explain that I felt hurt by the comment but he has reasoned that it's my fault for "making him say it". He said he didn't want to lie. But, why comment "fucking hell" in the first place? This makes me feel like he's disgusted by me.

Anyway we've not talked about it any more and have gone to bed but I'm lying here feeling so bad about myself knowing that my own husband thinks I'm gross. Am I over reacting? Please be brutally honest