My venting frustration

What is it with 1 year olds? I love him dearly but my word, he's driving me crazy since I have been back home from CA. Maybe it's the fact he spent 8 days with grandparents (nothing against you guys, I think he's doing it to get back at me for leaving him) and not mommy, but who knows. He now refuses to eat when he should be eating, even though the grandparents did a great job at keeping him pretty close to his schedule. Oatmeal ends up either in his hair or on the floor (sometimes me) while he just sits in the floor and cries because he is hungry. THat's what I don't understand. He's being offered food but he will not eat what is being offered to him. He would rather have animal crackers, graham crakers, or yogurt melts above everything else. I did get him to eat some eggs, bananas, and toast yesterday and a waffle on Tuesday. Today, I just put the bowl of oatmeal in front of him and a piece of bread and cheerios and he ate more than he did yesterday. Needless to say, I had a nice mess to clean up. That's as successful as breakfast has been this week. Lunch and dinner hasn't been any better. He refusted to eat last night so therefore, he ate 4 chicken nuggets and a little applesauce at 845 last night. I think this is affecting his sleep as well because he's now waking up at 4 or 5 am crying because (my guess is anyways) that he is hungry. In turn, this is also affecting his nap times. I am just frustrated I guess and am blaming it on myself for going out of town and leaving him for a week. Does any one have any suggestions about what I can do to get him to eat again??? Please, anyone??? Sorry, this is the best update I can give right now because this is what I've been going through all week. Maybe it will get better as the weekend progresses.