Bleeding at 2 weeks pregnant??!

Hi I am two/three weeks pregnant and been having the usual lower back pain, cramping, fatigue etc but today when I went to the loo I noticed pinky blood on my underwear and on the tissue when I wiped, this only started today. I'm worried I'm losing the baby? My doctor wont see me today so Monday will be the earliest I can see a doctor! Any ideas or advice? I'm going out of my mind!