Question about my dogs health... kind of worried!?

I have a 5 year old 80 pound male black retriever. I was informed that he was up throughout the night vomiting with diarrhea. When I woke up this morning he seemed to be his usual self, I was trying to make sure not to get him to excited. He proceeded to vomit foamy yellow all over the couch with almost no warning and when I took him outside he proceeded to vomit this foamy yellow on the porch. He tried to poo but couldn't and my mother does not think we should feed him right how however I am not so sure its a bad idea. We live in a rural area and it is sunday so most vets are not open today (not that we would have the money for a long vet visit anyhow). I am worried because as much as we try to dog proof the house for him he seems to have a knack for eating things (hair elastics, paper, toilet paper) and this worries me. . . . He seems to have his same demeanor about him except for of course when he is being sick... I am wondering if anyone has any suggestions?