Sleep training for baby

Hi my baby boy will be 2 months on 17th dec but I still struggle with nursing sometimes he takes breast milk and seems satisfied but there are times when I feel he is not and I have to unwillingly give formula…. On an average I nurse about every 1.5 hours for about 10-15 mins… I get sore and damaged nipples also due to regular short period nursing and again I either pump or give formula due to less supply….due to all this I feel my baby doesn’t sleep at a stretch at night usually the wake window is 1-2 hours at times 30-45 mins as well. Very rarely he has slept for 2.5 or 3 hours at stretch… please can anyone help or suggest