3 year old fears?

I am in need of some advice, or suggestions, Raelyn loved swimming last year she would splash, dunk her head in, and get so excited and play so hard she wore her self out. Then in March we took the kids swimming in St. George and she loved it still she even fell under the water and just laughed about it. Then in May she was suddenly very afraid of even getting in the pool. I finally got her in and she played for a few seconds and then cried and screamed until I sat on the side with her. I asked her about it and she said she didn't like the pool (we were at the club house pool at our old house) she said if we went to the yellow slide pool (Lindon) that she wouldn't be scared. I decided to take her swimming for her birthday at the yellow slide pool and she was so excited to go. We got there and she was a little hesitant to get in but got in and played for a good 5 minutes then out of no where said she was done and screamed and cried again. They have gone swimming a few times with their dad and I don't know if something happened to make her scared or if it's the age? I don't know if I keep taking her and see if she gets used to it? Or if I should find a babysitter for her while we swim?  I am open to any advice or suggestions!