Breastfeeding

Baby refuses to latch and my boobs were so large and firm I started pumping to get some relief. She never stays on and if she does she just falls asleep at the boob. I think I want to pump full time just waiting for my electric pump to come in I've been manuel pumping. My milk hasn't come in it's still colostrum but my question is.. If I haven't put her on the boob in a while and ONLY pump my colostrum can it lessen my supply? I feel like I'm starting to not be able to keep up with her feedings even though I pump multiple times a day I feel like my boobs aren't as rock hard and after a while they won't even pump anymore. Don't know if I'm just overthinking