1 month old throwing/spitting up breastmilk

So just in the last week my LO has started spitting up more and more after I nurse him. Then the past 2 days he is actually throwing up all of the breast milk right after and then continues to throw up a little bit for an hour or so. Has anyone else experienced this? Not sure if it's something in my milk making him throw it up but my diet is very normal and hasn't changed. He doesn't seem sick or anything besides that.