Someone help me put my mind at ease!

So I’ve been have so light cramping and absolutely no bleeding or anything to suggest a miscarriage but have had clear discharge so tonight went to the hospital because the cramping and was told that I’m only 5 weeks 4 days and not 8 weeks 4 days like I thought. So my periods are irregular but my last one was December 11 so now I’m confused and worried that I’m going to lose the baby because I’m like 2 weeks behind what I thought. Is that normal? They said everything looked okay but diagnosed it as “threatened miscarriage “ which is terrifying so I just need to see if anyone else had been through something like this and had a healthy pregnancy!