I am hurt. A plague o' both your houses! I am sped. Is he gone, and hath nothing?
Tybalt manages to cut Mercutio even under Romeo's grasp and Mercutio gets upsets and curses both families. One because Tybalt hurt him and Romeo because he intervened and got him hurt.
I do protest, I never injured thee,
Romeo does not want to fight Juliet's family due to his love to Juliet
Prodigious birth of love it is to me, 770That I must love a loathed enemy.
Juliet learns that Romeo is a rival familys son and she now hates that she loves him because she knows they could never be.
Then move not, while my prayer's effect I take. Thus from my lips, by yours, my sin is purged.
Romeo is telling Juliet that if her kissing him was to make her a sinner than she should only stand there and not kiss back
If I profane with my unworthiest hand
Romeo grabbed Juliet and for that his hand is unworthy of touching her again.
I have a soul of lead So stakes me to the ground I cannot move.
Romeo speaks to him not being able to dance and being afraid of being frozen in front of all the guests.
I would say thou hadst suck'd wisdom from thy teat.
the nurse is uplifting. making a joke about who Juliet got her wits and remarks from.
mine own fortune in my misery.
romeo is speaking to having a bit of wealth because he is able to escape into his books and forget of how heartbroken he felt.