If you have had unprotected sex, then yes you could be pregnant. It depends on how fertile you both are. The additional bleeding could be implantation spotting, when the fertilised egg attaches it's self to the wall of your womb, or it could be nothing.
I would suggest taking a pregnancy test, you can get them from most supermarkets and chemist and they are a reliable source to find out if you are pregnant or not. However you will need to wait to your next period before you can do it.
There are other signs that you can look for in the meantime -
- Missing a period - this is the most obvious sign, if this has happen it is worth taking a pregnancy test. Obviously you will not be able to do this till later on.
- Morning sickness - this effects everybody differently. You can just feel sick or you can vomit, or you can be lucky and not have it at all. Also it is worth remembering that it can strike at any time of the day not just the mornings!
- Going to the toilet a lot - with all the hormone changes that happen during the first trimester it can make toilet stops a lot more frequent.
- Feeling exhausted - it is a side effect of the rise in the level of progesterone in your body.
- A funny taste in your mouth - usually a metal taste. It is also normal to go off everyday things like tea and coffee. Personally I went off warm milk (so I had black teas) and yoghurts.
- Changes in your breasts - your areola (the skin around your nipple) becomes noticeably darker and bigger.
To be honest there is no real way of knowing until the 17th.