I can sing this poem..like a rap song..i loved it .lillie..

I feel the word poison is over used. its in everyone of the first four stanzas. maybe try other words like concoction or elixir?

I like how you choose to rhyme.
It gives your poetry an air of innocence and works very well.

Interesting that you chose the word injected in a love poem, almost has no place, then we look at you calling posion 'sweet' and it all ties in and works well.
I think you could trim line 4 back a little, the pace of the first three lines is very similar yet this is a little meaty.
maybe this;

Sometimes, up for hours thinking, see the sun turn into moon.

same message but written more punchy.

bye should be by in stanza three.

rather than 'got addicting' how about 'was addictive'

then with this line;

My heart aches, our love is lost in a whirlpool, this situation is quite sad.

trim back to

Heart aches, love lost in a whirlpool, situation is sad.

then with this line

When you do come knocking my way, ill answer with a smile.

just a little tweak to

When you come knocking, i'll answer with a smile.

Cant should be can't in next line

then I would lose the repetition in the final two lines, it is not needed,

One day our hearts will collide.
In your arms i'll be able to hide

just a few suggestions, your poem, tell me to 'do one' if you like.

Nice sentiment throughout, just make the pace more even, maybe even introduce a syllable count and you will have a really good love poem.