Weddingbee boards

I had my hair trial yesterday and it went pretty well. I liked the way it looked at the salon, when she was done:

However, as soon as I got home (went straight home from the salon), it was already beginning to fall out:

She used a ton of bobby pins, and mentioned that she tends to overuse bobby pins so the style doesn't fall apart. She also said that with this style, even if it becomes looser throughout the day, it still looks good. However, the curls continued slipping out throughout the day and it began to look messier and messier, and lopsided in the back.

My questions: how do I prevent this on the actual wedding day? I'm going to put gel in my hair the night before (we didn't do this for the trial); will that help? Should I ask for a style that requires less elaborate pinning up? Do I bring the last two pictures to the day-off and just explain what happened?

I'm just worried that my hair will look like a mess by the ceremony, which is four hours after the appointment; especially since this is how it began to look 30 minutes after the trial. Thanks if you read this whole thing and can give me any tips!

@nannettenicole: That's a good idea. Better than doing a second trial ($$), but it will make me feel better to settle it before the day of.

@SanDiegoAli: Thanks! Nope, I made sure to wash the night before. My hair holds a curl well, but it is kind of slippery even if it isn't freshly washed. The woman who did it was really accomodating... I think/hope she'll work with me to fix it somehow.