spotting after BFP and now fainter line???

Ciarra
Feeling nervous!  I got a BFP Wednesday the 22nd. I took three tests that day. Then I got one Friday the 24th just to be sure. Yesterday the 26th I spotted in the evening. And my BBT is lower this morning than it has been. I'm nervous that I'm miscarrying  already. Has anyone else experienced spotting and had a successful pregnancy?
Update: 
I also just took another tester this morning after posting this and I can barely see a line now....