Drs appointment today!

Okay so I'm 28 weeks and 3 days and have my Drs appt last time he mentioned to me that I'd be getting my glucose test but didn't tell me whether or not I had to do anything specific. And I've seen on here that lady's Drs would have them fast? Keep in mind I live in a VERY small town and my dr only has a special interest which I'm kind of concerned about but I have to deal with it I don't want to drive 3 hours for a Drs appt let alone don't have the funds to do it