First has he started sleeping during night time? Usually newborns will be sleeping during day time and active at night... this rhythm usually goes off by 1 to 1-1/2 months and they start sleeping at nights. If this rhythm is not set, it might be his routine to cry at night.
And by gas do you mean he passes flatus every time and cries? If yes, along with drops please try to incorporate these in his routines
1. To burp him after each feeds. i.e. to put him on your shoulder with his tummy pressed on your body and making gentle pats between his shoulder blades so that he belches the air out.
2. When you give massage
before you give a bath, add these strokes to his tummy.
Circular strokes around his belly button,
Stroke in the form of inverted L starting from right lower end, then up to right upper end and then horizontally to left upper end of his tummy,
Stroke in the form of inverted U starting from left lower end, go up, then come down to right lower end of his tummy.
Repeat each of these 3 strokes GENTLY 4 to 5 times.
If you do these as routine, his tummy problems will come down. But do it daily as a routine.
Also if he cries excessively pulling up his legs, take a warm towel (dry and warm) and place it on his tummy. May give some relief.
And breast milk is best. Some kids have more of such problems with formula. So try to give nutritious diet to mother so that she can produce adequate milk. Once you start supplementing, baby`s sucking on breast will reduce and in turn mother`s milk output will further decrease. So till 6 months of age, baby should be on exclusive breast milk only. It has numerous benefits.
Hope you find my answer helpful.