Breastfeeding how many times to wake during night

My baby is 3 weeks old and gaining weight well. All day she eats roughly every 1 1/2 hours - 2 hours. If she will sleep a couple hours longer during the night is this my chance to catch up on sleep? Or should I still get up and wake her to feed? Or wake up and pump? If I go any longer that 2 hours my breasts get super sore... but I also haven’t gotten any sleep in the past couple weeks and wouldn’t mind a 3-4 hour stretch. I don’t want it to effect my milk supply though and am paranoid...