Low HCG

Hello - I'm a little confused and not sure what to think about what my doctor has told me. I had an IUI May 21 and am 5 days late. I had a blood test done on Monday and HCG level was 38. 
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​Doc called today to say we did conceive but that the pregnancy is not viable because the level is too low. She also said that she would like to see the number go down and not up. I have another blood test Friday. From other things I've read, low can be normal and if number goes up it can be a good thing...
​Anyone had a similar experience?