Am i over reacting?

My SO works as a construction worker and i stay at home with our 1 1/2 year old. He will get home walk past our baby go out to smoke while im making food. Last night we were in bed when our son woke up. I get that he works so much but he didn't get up with me to take care of our son. I told him we needed diapers and he didn't go out to get any. Long story short it's like this every night. With no help, diaper changes. Im just so tired of it all. Being a stay at home mom is a full time job too.