I'm Chris. My second daughter, Brianne, had projectile vomiting when she was a baby. Our first never did, so we asked the Dr. He said she'd outgrow it... probably after 3 months. When she didn't, he said ... probably 6 months. Then well, 8 or 9 months.
She did finally outgrow it, at about 10 months, I am happy to say. Like your baby, she continued to gain weight, so I knew she was getting the nutrition she needed in spite of the situation.
She's 29 years old now! My husband and I have laughed over the years about how he wouldn't hold her at church (we couldn't afford to send his suit to the cleaners every week). Once, at church, we were sitting on the back row. I put a receiving blanket over my shoulder, and over the back of the seat. (little burp cloths were senseless for her)- you know- She burped and spewed OVER MY SHOULDER. My shoulder and back were dry, but the floor three feet behind me was soaked... What can you do?
There will be a time when it's over, and maybe 30 years from now, you'll be able to laugh about it!
I feel your frustration! You are not alone. I'm glad you checked with your Dr, tho.
We went on to have seven children, none of the others had this problem!