Hi Nell,
It is safe to travell inthe 2nd trimester. I know this cuz I went to England and Scotland in May of this year. I was 14 weeks pg at the time.
Its only your 3rd trimester you aren't meant to fly just in case you go into labour. But you'll be back way before then!!!

Have a great time in Fiji... I was there for my brother's wedding in Aug last year. We had a ball and had wanted to go back (as a group again) for their first anniversary this year, but I'll be in my 3rd trimester and can't go with them. It is a GORGEOUS place!!!