Due date not accurate?!

Tia
I went in this morning for my "28 week" growth ultrasound and glucose test and due to gloomy weather it caused their computers to shut down so my ultrasound is showing baby measuring almost 30 weeks and my belly (fundal height) measured almost 32 weeks. Needless to say I now am kinda in limbo and don't know exactly how far along I really am. Has anyone else experienced anything similar? I'm nervous because my baby shower may be my new due date lol