My last period was December 6, 2015 I had unprotected sex on 12/17/2015 I was due for my next period on 12/31/2015 I took a hpt test the day it was due and it was positive I was having abdomen pain so I went to the emergency room to get checked out they did a papsmear blood test and ultrasound then they came and said we know you are pregnant but the blood test hcg is low they think I was about 3 weeks and the ultrasound shows nothing they told me to come back to the er or see my obgyn today I just need to know now before I go what is going on

Ask your OB/GYN when you go to the meeting today.

No way to tell you what's going on, which is why you need to actually see your OBGYN. It could be that your pregnancy isn't as far along as they say, which would account for the lower hcg levels. Or it could be that you were pregnant, but miscarried, but without bleeding I would find that odd.

At 3 weeks there really wouldn't be much to see on an ultrasound. The fact that they said you're 3 weeks and they didn't see anything on ultrasound, is an even better reason to see your OBGYN. Doesn't sound like the ER doctors know a lot about pregnancy, from what you wrote. But then, most ER doctors don't. That's why there are doctors that specialize. An OBGYN specializes in pregnancy and women's health issues. Best to talk to your OBGYN.

Good luck.

Let me know how it goes. I hope it turns out the way you want.

At about 3 weeks, hcg can be very low and ultrasound inconclusive for pregnancy. Have you seen your doctor? Another blood test to check the hcg level now would tell them more.