Hoping for the best

This is my first pregnancy. I was told I wouldn't be able to get pregnant without fertility treatment but they were wrong. Found out found out last Wednesday was pregnant. It said 2-3 weeks. Thursday I started spotting. It goes from brown to red and back to brown but no tissue. Took the second blood pregnancy test yesterday but no word from doc yet. Took a home one last night. Still positive but now 3+ weeks. Is this a good sign?