My line hasn't progressed?

It's been 48 hours and my line has only gotten slightly darker. I'm worried this might be a chemical pregnancy. And honestly heartbroken. The line is very faint and light pink. Has anyone had this before? UPDATE: I took a digital it came back negative. So I've decided to book an appointment to the doctor and take a blood test. I feel that by this point the line should be much darker. Wish me luck.