If your teeth are sensitive when you brush, you should change your toothpaste, right?

My gums keep feeling sensitive whenever I brush, so I'm thinking of switching toothpastes. Could you recommend any toothpaste for sensitive teeth?

I've had swollen gums and seen blood occasionally, but this is the first time they've been this sensitive, so it's really stressing me out. I've heard that using toothpaste for sensitive teeth helps; which one do you recommend?

The reviews for Mas toothpaste are good, so I'm thinking of giving that a try as well.