Unusual period while ttc

My husband and I have been ttc for just over year now. I just took my 3rd round of Clomid 100mg. By cd 35 I still haven't started my period so my Dr ordered a blood test. The next day it came back negative and I started my period. That was on a Tuesday. Wednesday I bled pretty heavy, Thursday was light, Friday I was spotting and it's now Saturday and I'm no longer bleeding. All the time I was bleeding it was a dark brown almost black color. Never once bright red. I didn't know if by chance the test could have read a false negative. Or if this is not normal and should see my Dr asap. My periods usually run about 5-6 days and I've always had a bright red color. Any input would be helpful. Thank you.