The Sick Rose is a truly layered poem. I think every person I discussed it had a different interpretation of its meaning. Hannah thought it was associating with cancer, I thought it was relating to rape, several people found it to be exploring lighter topics like a tragic romance.
The two main personified characters in the short two-stanza poem are the namesake sick rose and the invisible worm. The invisible worm is a perfect metaphor for a veiled and undetected diseases so ten points to Hannah for that one 
The invisible worm is also what makes me think that is this poem truly does talk about sex, its not consensual because it seems to suggest that the worm was something the rose didn’t see coming.
The rose’s bed (that’s a pretty apt pun because if the rose is in a garden, it’s probably residing in a flower bed, by the way) is described to be ‘of crimson joy’. Now that may just be a commentary on the colour of the rose and joy may be meant sincerely as to describe the state of the rose before she (yes, I’m feminising the rose) was infected. However, because I’m a depressing person, I chose to see it as an analogy for the bloodshed of the virgin, the word ‘joy’ being sardonically ironic as sex is meant to be consensual and enjoyable not symbolic of the stealing of someone’s basic rights.
The last two lines of the poem seem in accordance to this ready as the ‘dark secret love’ of the worm ends up destroying the life of the rose. Dark secret is a good word choice as the consonance adds to the emphasis on the words but what’s even more intriguing is calling an act of rape, if that is indeed what the poem is talking about, ‘love’. One might argue that Blake did call it dark so perhaps he means a twisted version of love, but can such an act of raw lust be any kind of love? I guess it depends on which philosopher or psychologist you’re referring to. Anyway, did anyone have an alternate reading of the poem?
