Looking for advice on what to wear for first sprint tri

Hi everyone. I'm getting ready for my first triathlon. Started training last September and the race is coming up August 8th. I'm wondering about what I should wear duing the race. I did a time trial (800m in a pool, 18mi, 3.1mi) a couple weeks back, and there I wore my swim suit for the bike and run. Problem is, I got pretty uncomfortable by midway through the bike and found myself getting out of the to "rest". Last week I tried slipping my bike shorts over my swim suit, but that caused some chaffing that wasn't fun. So I'm wondering if I should just swim in my bike shorts, and wear those for the whole event.