My DD had reflux. An osteopath told me that reflux can get worse with growth spurts (DD got much worse at 3 weeks old). This is because the diaphragm, which is the muscle that surrounds the top of the stomach, does not always grow in synch with the growth of the child, so it needs time to stretch. With DD, she gets frequent bouts of hiccups whenever she has grown alot, her reflux gets worse and then gradually settle down again.
When you wind your DS, only gently rub his back - do not pat it. Patting can trigger the vomitting. The trouble with wind and reflux is that if the wind comes up in one big bubble, it needs the top of the stomach to open wide, which allows loads of milk to be brought up at the same time.
With DD, I found that all the winding in the world did not help. This was because she did not seem to be swallowing air while feeding, but generating wind over about 30 minutes after feeding. If this sounds like your DS,
I suggest you ask your GP for a prescription for Colief. You add it to milk (whether ff or bf) and it helps to digest lactose. If your DS is not fully digesting lactose, the bacteria that are naturally in his gut will digest it and produce wind as a result.
Do you have the cot elevated and also his change mat? If he is uncomfortable, try lying him along your arm, face down (tiger in the tree position). The pressure on his tummy may help him to feel more confortable.
Gaviscon did not work for DD, but I am aware that it does help some. There are several other medicines available to treat reflux. So, persist with your GP until you get something that helps.
Finally, it really does get better with time. DD is now 2 and has very few problems with reflux. So hang in there!