Last night I had a random episode of slurred speech...

Let me start by emphasizing that I have an appointment with my doctor tomorrow. If it happens again I will go straight to the hospital. I simply want opinions/ideas.
So I'm 25, no previous medical conditions. 17 weeks with baby #3.
Last night I randomly felt confused, my speech was slurred like I was drunk and I had trouble processing my thoughts. This went on for about 3 min. After ward I had a terrible headache. I took Tylenol and it eased up after 40 minutes or so. 
Lately I've noticed my vision is a bit blurrier than normal even with my glasses on and I've been having frequent headaches. I attributed this to pregnancy until last night. 
Has anyone had a similar experience or have any ideas as to what could be going on? I just want to pick some brains before my appointment