["My friends left on a trip, but I couldn't go with them because I have so many projects to work on.", 'That had to be disappointing. Will you be able to go at another time?', 'Yea definitely. I hope we get another time sooner than later.']
At least you have something to look forward to.
My friends left on a trip, but I couldn't go with them because I have so many projects to work on.