Miscarriage On My First Pregnancy

Hi, I've missed period for almost 2 months now, i supposed to get period on Dec 28, 2009, haven't get any until now. I'm 26 years old, and have an irregular period until after I got miscarriage on my first pregnancy on April 23rd, 2009. Starting yesterday, I got light brownish spotting on my underwear which i don't think it's a sign of period, because it should be getting heavier by now. I have no cramping, no signs of pregnancy (not like the last year's pregnancy), home-tested 4 for a month and came out all negative. I'm puzzled right now. I'm planning to have the test again tomorrow morning. Please help me with all the possibilities I might have. Thank you.