Dizziness

Jenni • Married. 1st son is almost 2, pregnant with baby #2 due June 11th
I've been having severe dizziness all day today. The onset seemed pretty sudden too I was a teensy tiny but dizzy a couple days ago and now all the sudden I've been super dizzy all day. I ate a good amount, didn't do anything out of the ordinary. Even typing this right now my screen is spinning. I can't call the doctor because they are closed for the weekend. Every time I've ever called the nurse line they tell me to go to the hospital which has never actually been necessary, so I don't feel like it helps to call them. Any suggestions? Anybody else experience severe dizziness or have an idea about the cause? The last time I checked my blood pressure (a few days ago) it was really good: 102/66. I'm 16 weeks pregnant with baby #2.