GERD ? or a phase?

My little girl is almost 3 months old (in three days) and maybe the past few weeks cries after every feeding. She is bottle fed and drinks Soy milk bc she had a little milk allergy at first. She drinks 4oz every 3 hours and weighs 14 pounds. My husband and I thought maybe it's because of the nipple size? But I doubted bc she spits up a lot and throws up almost every feeding. She is gaining weight just fine and it's just recently I've had to worry about her spitting up all her milk. I use to feed her every 3 hours even when she didn't tell me she was hungry and I thought well maybe that's why, because she wasn't really hungry. Now that I don't do that I feel like there is spit up more than ever and more throwing up. Anyone think it's GERD? And should I contact doctor or wait until her next check up?