[Or maybe this was a bad time. He'd hoped that would be reassuring, not... whatever it apparently was. He should have waited until he's had an opportunity to sort himself out or for a less confusing moment or until Kitty said it first. He's been waiting for what seems like forever, thinking the words but always too uncertain of Kitty's potential reaction to say them. Waiting a little longer wouldn't have hurt him.
Chekov cares so much and so quickly and doesn't try hard enough to reign that in. It's worked out for him for the most part. His family loved fiercely and without hesitation, and his found family--the crew of the Enterprise--were immediately close thanks to the dangers they've been facing together since before most of them were technically officers. Lucy was fast to love, too. The same can't be said of the various not-quite-girlfriends that he's had at home, but...
This is different. This really matters.
Chekov isn't hurt. Disappointed in his timing and in the outcome, yes, but not hurt. He would have said it much sooner if he'd thought that she would reciprocate.]
You don't need to feel the same. [Just don't tell him to go. He only got back this morning.]