I wouldn't worry too much cats are a lot more robust than we think! My cat has just been away for 3 1/2 weeks, a 2 hr journey from home which included 2 car swaps as I drove part way, my friend drove the rest. I was dreading it!
She stayed in a vet hospital for thyroid treatment. She is a very pampered and spoilt cat too, and very nervous of strangers, especially men. But she settled in really well there and they said to keep her in for a few days when she came home, but she back to her normal self within an hour, following me around, purring, eating, etc. I thought she would be traumatised having all these different people prodding and poking her for a few weeks but she was fine. Go ahead and enjoy your trip and I hope the IVF goes well