Heavy lifting while pregnant

Hi, I’m 32 weeks pregnant and so I was at Walmart today and got a mattress, one of the ones that come in a box and expand. 75 pounds max. It was only a twin. I lifted in onto the cart and out of the cart, then slightly into my car and slid it the rest of the way in. This was 4 hours ago, I don’t feel pain but in my back which is normal everyday. I’m getting a slight pain at the top of my belly in the middle but I get that from even lifting my 11 month old. If I’m feeling no pain and the baby is moving like crazy, it’s ok right?