Ay nak, I understand your worry, the umbilical cord can be scary, talaga! But please have your baby checked by the doctor or midwife today to make sure everything is okay, lalo na may bleeding pa, hindi magpabaya, okay?
At 15 days old, the cord should be mostly dry na, so any fresh bleeding needs professional eyes on it, hindi lang sa bahay. Maraming reasons pwedeng maging cause, pero yan ang makakaalam talaga ng doctor after checking. In the meantime, keep it clean and dry like you're doing, wag i-disturb, at pag may doubt, dalhin agad sa clinic. You're doing great as a mom, nak, better safe than sorry with these things.