I really liked this poem. I think you did a great job at defining the pain of relapsing something as hard as depression, or just something that no one should have to deal with. I especially loved the lines,
"The past rests on my shoulders
Always bringing me down"

And I really enjoyed the last stanza. I think it completed the poem and provided a sense of inspiration, of hope.

One thing: This line confused me a litte, "That's drug on ever so slow."
I think it needs to be worded differently, or perhaps revised because I couldn't really figure what you were trying to say.

Overall I thought it was a good read, nice job.