Why do my fingertips (right under the nails) feel cold, clammy & uncomfortable?

They feel like this ESPECIALLY when I'm feeling anxiety. But right now, I feel them, & it's increasing my anxiety, making me come close to an anxiety attack. I HATE this feeling SO much! & it's also usually around the time when my nails NEED trimming & are too long, or when they're FRESHLY trimmed. After a few days, they're fine again. But I HATE this.