I'm just an amateur so take this with a grain of salt. Unless you have strange malady in your fingers it sounds like you are just psyching yourself out, maybe especially because your diploma is coming up. If that's true, you need to find a way to release the tension. You might try just giving a little lift with your upper arm and elbow and then dropping onto the trills - really a very small motion. Sometimes I find that an arm motion like that releases tension that has built up in my fingers. And for a long trill, see if just moving the elbow a little bit, say in a small, slow circle, doesn't help you release tension in your hand and fingers.