Bedwetting Support Group
Bedwetting (or nocturnal enuresis or sleepwetting) is involuntary urination while asleep. It is the normal state of affairs in infancy, but can be a source of embarrassment when it persists into school age or the teen or adult years. Find others who are coping with a bedwetting problem and share your experiences and questions.

https://www.dailystrength.org/group/bedwetting/discussion/i-started-bedwetting
You’ll find a lot of tips. Enjoy your trip !
How is your baby?
The next morning you can get up earlier than your roommates and go to the separate room where you can dispose your wet diaper. Nobody will notice. If they notice, explain them that you need to wear diapers because you’re pregnant.
I hope your school trip went well.