eating less after shots

My baby had his 2 month vaccines on Friday and he had a slight fever and was very cranky on Friday. We did a lot of cuddling and a nice bath and he slept from 8pm to 5:30am and seems to be feeling better. The only thing I have noticed is that he used to eat about 3.5-4 oz of breastmilk at each feeding and now it's only about 2 oz each feeding. He also seems restless while eating. He will start out ok but then he gets very squirmy-- I thought it was a burp but I think he's just done eating. Is this normal or should I call the dr?