Got positive on First Response Test, Low on Blood exam 18 hcg and now brown discharge?

Hi, My cycle is irregular, my last period on May 19th 2009, on June 18th I use a First Response Test and it was a Faint Positive result, so I went to my doctor next day and the blood test came with 18 hcgm my doc told me it was low and to come back next week, it is now 3 days since my blood test, and 5 days before the next doctor appointment and I got brown discharge, could I be pregnant? or did I have an early miscarriage? or was it a false positive? or is it my period? Notes: I've being having the cramp sensation as when I am getting my period. My cycle varies from 23 days - 35 days but the past 5 period cycles where lower than 29 days cycle, just a 33 day on past November 2008.

[JoyRenee]

Many things could be going on. It's important to get your follow up blood test. If your levels are doubling every 48-72 hours then that's a great sign. It doesn't matter what the level is so long as it rises.

Sounds to me like you may have tested early. Your levels have to start somewhere.

[LosingMyMindInGA]

As Joy said, your levels could be low becuase you tested early.  I had the same thing happen to me but my outcome wasn't good.  I had several faint positives...went to doc becuase i was spotting brown. they checked my hcg and it was low...gave me a shot of progesterone.  Didn't work...several days later I was full out bleeding and cramping like mad.   But we will pray that in your case its just that you tested early.  Don't give up hope until you see what the outcome of the next test is.  As Joy said if they are doubling that's good!