Help with breast feeding

Hi I am 21weeks post pregnancy and till now I am feeding breast milk via pumping since day 1 my baby is born. Now my nipple hurts and it’s way too big just because of pumping like 4- 5 times pumping a day but now I reduced numbers and come down to 3 times. Today I noticed that my skin under my nipples is cracked and it’s bleeding 🩸 and my bottl milk was full of blood. So just wandering how long should I pump and if I should start formula. Or start with solid please give me some advice.