feeling a bit hurt by my husband

I'm 38w, fed up and wanting to stay active so baby hurries up and comes. 
I paid £20k for our new car about a month ago and it's absolutely filthy and covered in dead bugs etc. We haven't bothered washing it because it's been raining all week. 
Finally from today, we have lovely sunny weather for a while and I've been saying I want to wash the car. I've been nothing but nice to him and we've got on really well this weekend but he suddenly snapped at me this morning and said 'your obsession with the car is really grating on me'
I feel ridiculously offended by it as he is the one trying to get me to be active and keep moving. I've been wanting to clean it and keep it nice for bringing baby home since we got it. I'm desperate for the activity because I'm SO bored now and he just made me feel really bad for it. Just out of nowhere and he doesn't say a bad thing about anyone and never puts me down. 
Any thoughts on this?
Edit: it's a very big car and I can't do it on my own. 
He just never ever feels like he should say sorry. EVER.