Poetry can be difficult to correct as some grammar rules get ignored for the sake of art. Some things are open to interpretation, but here is how I would write it :)
The red highlights are for clear mistakes, and green highlights are for changes I don't think are necessary but make it sound nicer.
SWEET THINGS
Everytime I see you, it's like the first time.
I would sleep and dream of you because if you are in my dreams my day is wonderful.
If nothing is forever, would you be my nothing?
Our love is a promise and I want to keep it.
I would be with you in every single moment to hug you and tell you how deep is my love.
Our love is like the shining stars in the night, our love is beautiful and colorful like a petal.
It's enough to see your smile to understand how beautiful it is get a daydreamer.
The last sentence I'm not confident on. I'm afraid the original line is a bit too confusing for me to understand your intent, so I couldn't correct it without changing the meaning, sorry about that. But it was fun correcting your Sweet Things, thanks for the smile :)