Help lifting heavy things!

Ok so me and my fiance had to change two flat tires last night and I was the one who picked the aired up tires up and took them to the car I only lifted one and then took the other two flats back to the car one by one.they weighed aired up about 30 pounds and felt like nothing flat.I am 30 weeks pregs with number three haven't felt any pains or anything and misterman moves around constantly.should I be worried I hurt him or could go into labor early?? Never did this with first two but kinda had to bc no one else would help him out and I didn't want him to do it all alone.