first pregnancy and scared

My last period was April 3. It was abnormal so today we had a sonogram to see how far along I was for sure. They couldn't see anything in the sonogram. Then they did bloodwork and said my hcg levels are there but they're only saying I'm like 2 weeks. The nurse made it seem like that could be a bad thing. She told me to come back in Friday and redo blood work to see if my number increase and in her words "see if my pregnancy is ok". Now I'm freaking out thinking something is wrong. Me and my husband have been so excited after TTC and getting a BFP but today has just been a slap in the face. Anybody else go through the same thing and how did it turn out? I just need some answers.