TMI - Should I be worried?

I had some pinkish spotting last night. Then nothing all day, then a bit more when I got home from work. Clinic says it could be implantation blessing (I'm 6 weeks 4 days) because this is the time the embryo digs deeper into the uterus. 
Anyone else have this issue and go on to have a viable pregnancy? This just doesn't seem normal to me!??