Vomit and spit up more than normal

M

My son is 4 weeks today. He doesn’t have a temperature and we are monitoring him closely. He has vomited 3 times in the last 4 hours. Seems fussy and only wants to be held. I’m a ftm. Should I take him to the ER or wait and see if he gets a temperature? Is this normal sometimes? It’s so hard not knowing these things.