“I cannot bound a pitch above a dull woe, under love’s heavy burden I do sink.” Whatdoesitmean??

Question

from Shakespear's "Romeo and Juliet" play. Act 1, Scene 4. in the folger's edition, it's on page 43, lines 21 and 22. thanks, bye(:

Answer 1

I think it means "I can't act happy about something, when my lover is sad about it." :\ I don't actually know.

Answer 2

they can do nothing but long for their loved one.  The only thing they can contribute is quiet grief without that special person.