Yellow spit up and projectile vomiting?

When I got DS up this morning, he had a yellow spot on his sheet and a little bit on his onesie by his mouth.  It looked like he had spit up yellow stuff.  Then everything was going normal when I was feeding him this morning and then he all of a sudden just started projectile vomiting everywhere.  He doesn't have a fever and he is acting pretty normal.  He's been tired a lot for the past couple of days but I chalked that up to starting daycare and all the activity going on around him.  He does have reflux so I am not sure if this has something to do with it.  Anyone have any experience with this??  Thanks!