Spit up !!

Any mommies experiencing a lot of spit up with baby ?? My son is almost 5 months and the last week he's been spitting up a lot. Exclusively breastfed and I haven't changed my diet too much. I am starting to eat a little healthier though. He eats every 2-3 hours and then just spits up. I try to hold out for 4 hours and I do notice less spit up but then he's fussy (I'm assuming becus he's hungry).. should I ask doctor about reflux or ??