I had multiple bleeds with my DD who is now 10mths old, one around 6wks which scared the hell out of me, one i think around 10-11 wks and one a little later in the pregnancy.
They say the one around 6wks can be from the egg etc implanting in your uterus and so on, the others they told me may have been caused by pressure during intercourse.
I was FREAKING to say the least.

#2 is on teh way now, am 18wks and so far (touch wood) no bleeds this time round.

I was told if the blood is brownish and no pain then try not to worry it's if you get pain or the blood dramatically changes color and becomes 'fresher' that you should get double checked.

Hope this helps, good luck i'm sure it will all be fine.