Hi Amy,
I had brownish - red spotting during this pregnancy when I was around 10 weeks... it lasted a few weeks and eventually went away... I had a very heavy feeling in my tummy at the time too... I had an ultrasound which confirmed that everything was fine and there was no real explaination for why the spotting was happening... I am now almost 28 weeks pregnant and have had nothing since.
Wishing you all the very best... I know it is scary, but it doesn't always mean something bad is happening.

Lisa