had sex yesterday and bled straight after, i think im pregnant as i had sex at time of ovulation and still feel pregnant, i am still bleeding but getting lighter and brownish with a little cramping, not due on till 8th june?

If you have had unprotected sex, then yes you could be pregnant.  Thought I will be honest I have never bleed straight after sex, the logical things which I think could encourage bleeding are -

• You were due on in a few days naturally
• It was your first time
• Your partners penis was rather large

However you can not really know if you are pregnant until 8th June, then you will be able to take a pregnancy test and find out for sure.  However there are some other signs which you could look out for whilst you are waiting -

• 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 frequently.
  
• 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.
  
• Unexpected bleeding or cramps - this is due to the
  implantation of the fertilised egg into your womb.  It happens during week
  3 and 4 and can cause some spotting.
  

Your bleeding could also be the last point above, implantation.

If you are concerned I would always recommend seeing your doctor.