Hugs Deb, I am sorry you are going through a rough time.
My DD was a fantastic feeder for the first 6 weeks or so and then started to get extremely fussy on her bottles. We changed her teats, and nothing. She ended up getting chicken pox from her brother, and this caused reflux to flare up.
She ended up going from drinking about 20 oz a day, us battling to get 5-6 oz in her a day. She did not spit up much, but when I watched her, I noticed, that when she did spit she would swallow it, so knew that the reflux was silent.
I would definitely keep an eye on her, and watch how she reacts when she spits up.