Experiencing LOW blood pressure...

Amanda • Mother of two wonderful boys and a beautiful little girl.
When does this become worrisome?? I have been out and about just about all day.. Well; I took my mother and two sons to the dentist for my oldest son's cleaning appointment... And when I went to park, the van didn't want to shift gears! Well; after that I couldn't get it to shift AT ALL; so after spending over an hour trying to get it to shift and get a tow truck... We finally got one and followed him to the repair shop... I was starting to feel woozy from a migraine then... Well; after that we dropped my dad off at home and went to my mammaw'so house... I was still woozy and dizzy but thought nothing of it. I figured my blood sugar had dropped, so I ate a few Reese's. (Usually those help when it drops...) well, they didn't help, so I checked my blood pressure; it was 84/45!!! I ate some salty chips, drank some water and tried to relax for a few minutes... Honestly; I felt like I was going to get sick and pass out. (Never did, thankfully!!) after about an hour or hour and a half; it finally came back up to closer to normal. I still feel a bit dizzy and just tired... I talked to one of my friends and she said it sounded like I hit a vagus nerve? (Not really sure I did... But I won't rule it out.) anyway; when would I need to be worried about this? (I've had issues with it being low the whole pregnancy; but not this bad... I'm 31 weeks and 3 days...)