Four-month-old baby, and we're still spitting up 4-5 times after feedi…

Four-month-old baby, and we're still spitting up 4-5 times after feeding. Sometimes with kefir, sometimes clear like water, sometimes milk. Without smell. I remember when breastfeeding in the hospital he didn't spit up at all... if you think about overfeeding then I don't think so... He eats 120 every 3 hours. Between them, I give him breast milk. But I feel that there is no milk in the breasts at all, it's not about mature lactation. He sucks but doesn't have gulps. And when I squeeze out a drop? We went to see a neurologist, she calmed us down and said nothing is wrong. It will pass... did