Glucose test

Just got a call from my dr I failed the 1 hr glucose test. I am so disappointed. I haven't been eating terribly and I always watch what I eat. I just don't understand what happened. I feel like I do everything in supposed to to have a normal healthy pregnancy. Just beating myself up. I have to do the 3 hour test later this week and I am just so upset I don't even want to go through it.