Firstly,try to give breastfeeds only,but if forced to give top milk feeds,use ONLY formula,NOT open milk. Secondly,maintain strict bottle hygiene if using one,and very important,give feeds at a gap of atleast 2-1/2 hours,not less. The commonest cause of vomiting at this age is regurgitation due to overfeeding. Keeping proper gap between feedings and burping him for 10 mins,AND keeping him elevated by placing a cushion beneath the head and shoulders will solve the problem of vomiting. About motions,the number of motions vary,as does the consistency,in babies up-to 4 months of life. All you have to do is give feeds at regular gaps,burping properly,and proper him up a bit. Strict bottle hygiene is a MUST!!