Better to be over cautious than sorry. I would be straight to doc to rule out pre-eclampsia. Every appointment I had I was asked if I had any vision changes - it's something taken very seriously. If you can't get in to your normal doc/OB just go to a 7 day medical centre for a blood pressure check at least. And if it happens again I would go to ER, better safe than sorry.
Hopefully is nothing, but please don't feel like you are being silly or OTT.