I Fight.

I won’t give up, however

Fraction of you fills an
Indent in me,
Gathering all my rage.
Hurting me over and over
Though I won’t give up.
I’ll push you back
Never letting up
Getting up again and again.

That was pretty cool, I've done the same sort of thing with the spelling on the side and it can definitely get tricky. Here's just a couple of small suggestions:

I won’t give up, however

Fractions of you fills an
Indent in me,
Gathering all my rage, Not a huge fan of this line.
Hurting me over and over
Though I won’t give up.
I’ll push you back,
Never letting up
Getting up again and again. I felt like the last couple of lines lacked any real impact. I would try to find a way to end this with a lot of force.

So overall I think it's a cool idea, it just needs to be strengthened a little bit. Do what you can to add depth without compromising the fact that you spell it across the side. It's definitely a struggle, but just try tweaking it without losing it.
Keep writing,
StoryWeaver

Hey Boo!

Well, I love the idea and the theme of this poem, and I am glad to see you trying different approaches. I find the "short and sweet" aspect of this rather pleasant (I hate long poems DX)

Now, I have to say that this poem is not alive. It needs much more imagery, and I see that you did put a bit in there, but it needs more. This poem is talking more than it is showing. When you add the imagery, it will make the lines a bit longer and more robust, which is a good element to have in a good acrostic poem.

I also see many other possibilities with this poem, though I am not sure how to properly convey them to you. Here is what I am about to do: I will not necessarily rewrite this poem, because you should do that on your own in order to grow, but I will show a few tiny modifications you might consider if you do modify it.

I won’t give up; however,

Fractions of you fill an
Indent in me,
Gathering up all of my rage. You
Hurt me over and over,
Though I won’t give up.
I’ll push you back, and
Never cease to
Get up again and again.

These are some things to just look at if you want to, but you do not have to at all.
Keep working on this one, it has great potential!