scared its breast cancer

So..i found out its not crack nipple and there's a lump on the nipple and inside the breast under the lump.milk would come out by itself even when breast is not full. I stop breastfeeding on that nipple because it hurts like hell when my baby suck.its been almost 1 week now. I would squeeze out the milk from that breast and it wont hurt. Maybe its because im not touching the lump.my milk production is getting low and my baby is getting temper because of it so i have to go for mix,breastmilk and formula. I really want my baby to be on breastmilk more. Its been 5weeks 2days since i gave birth and this problem happen on the 4thweek. What should i do to make the lump go away. Any mommies experience this before?