Really scared and worried

I tested positive Monday morning much to my surprise! I should be about 5w3d right now. I've had some mild cramping and lower back pain yesterday (also mild). And when I go to the restroom sometimes, I wipe and there is light pink blood about half the size of a finger prick. I have had nausea today as well. And I obsessively take tests because I'm so worried. My line on my hcg test was darker today than it was Monday. This is my first pregnancy and I am trying not to stress out. Any advice or ideas? THANK YOU.