Spotting?

I’m a little over 5 weeks pregnant and started spotting this morning. It started out thin and reddish and now it’s thick and brown. Not enough to stick to a pad, but enough that you can see when I wipe. I called my OB and they said to call if I get really bad cramps and a lot of blood, but I’m still worried sick. We have been trying for 3 1/2 years, so I’m really hoping this is out miracle baby. I did not have spotting with my first pregnancy, so this is all new. I hope I’m not miscarrying or about to.