Threatened Miscarriage?

I went to the ER today for extreme dizziness causing me to feel like passing out constantly. I wasn’t dehydrated, but my BP was extremely high. I don’t eat bad foods, smoke or drink. I have a half a cup of coffee in the morning. They classified it as a Threatened Miscarriage due to the dizziness and my blood labs. I’m 5 weeks. Should I be concerned? I’m terrified. Any advice with dizziness?