Possible miscarriage

Yesterday I went to the ER for light spotting and cramping that started that morning. They did a hcg level check and an ultrasound. I never had either one done this pregnancy as im waiting for my pregnancy Medicaid to come in. I was suppose to be 6 weeks 6 days along, based on my lmp. They told me my level was 500 and they didn't see anything in the ultrasound. I don't know what to think, I went through a miscarriage last year and I don't want to experience it again. Sorry for the long post, and I found out I was pregnant through a clinic but they wouldn't take me as a patient bc im high risk. Im praying im not losing this baby but I can't help but to prepare myself for the worst. I go back tomorrow for a another hcg level test.