What is the name of this poem and who is it by?

Question:

What is the name of this poem and who is it by?

I don't know how it goes exactly, but it's something like this:
"a worm has come in the night to make my love sick"
and then it says something like if you hold on to hope, it won't be good, but if you let it fly away it's good, or something...
Please help!

Best Answer - Chosen by Asker:

Is it "the sick rose" by Blake?

O Rose thou art sick.
The invisible worm.
That flies in the night
In the howling storm:

Has found out thy bed
Of crimson joy:
And his dark secret love
Does thy life destroy.