1 year shots

My son had his 1 year shots on Wednesday his had a fever since and it’s kind of gone down but he is still very fussy

He has completely stopped eating food or drinking milk he probably would have about an ounce or two after hours and hours when he gets very hungry I guess but it is really stressing me out I know mmr vaccine can cause loss of appetite a week or so later but his started from day 2 I’m struggling and don’t know what to do any advice? Experience?