I don't think I should get on my flight in the morning.
That sounds really dramatic! What's the matter? What's making you so unsure about it?
I just have a bad feeling and I think it'd be best if I cancel it!
I can understand trying to abide by one's intuition... Are you going on your flight to somewhere where you have something important to do or someone to meet? Perhaps it may be unfair to them or that situation if you don't go through with it. If you want to do it, try your best to think of all the repercussions, and to weigh the pros and cons, and to not let your intuition cloud your judgment.