Same thing happened to me around the same time as all of you guys...I didn't have cramps but I had light bleeding/spotting for 4 days. My periods normally last at least 10 days so I took a pregnancy test to make sure and it was positive!
However, I have been a mess since then. First I tried to make an appointment with an ob and told to go directly to the emergency room. They diagnosed me with a "threatened miscarriage/possible ectopic/early pregnancy". Went to an ob the next day and she told me that she was sure I would miscarry due to the low numbers and even after they doubled. Went to a new ob yesterday and waiting on results but still they cannot tell me if everything is okay or not.
I recommend not going to the er unless you are in pain or bleeding very heavily...because otherwise at this early stage it seems they just worry you with everything telling you all these possibilities when they really can't know anything ....