Our doctor - Dr. Tracie O'Neill at Pediatric Associates in Pine Lake is amazing. When my daughter had GERD (acid reflux) starting at 4 months old, she treated her first with standard meds (Zantac) but referred her immediately to a Gastro-Enterologist at Seattle Childrens Hospital as well.
To my layman's (but experienced in this case - since I had it as a teenager, and my daughter did as a baby) ears...it does sound like GERD....the pain due to excess acid (have you tried an antacid?), and then the blood is the irritated esophagous (sp?)...of course it could be something else, but the symptoms are what I and my daughter had.
I would get her in to see a gastro-ent doctor as soon as you can - it seems less likely to be OB-Gyn related if she is spitting up blood.
good luck,
K.