It is very valuable to have an opinion from someone like JennyW. It is not likely that you will encounter many individuals who have served time on an admissions board in the field that you wish to enter. I have read many posts from her, and she knows what she is talking about.
However, I also believe (albeit maybe naively) that anyone with around average intelligence can accomplish anything worldly that they wish, IF they have the determination and resolve required to do so.
That being said, if you (kristykan2003) know in your heart that optometry is exactly what you want to do, and nothing else would satisfy you professionally, then you can make it happen. It is going to take some serious dedication. It seems that you have a great deal of dedication already, if you have taken the OAT twice, and I sincerely hope for you that you can get it up a bit. Nothing is ever 100 % for sure, not what JennyW says, and not what I say, but I believe that you should not take discouraging posts too seriously. For example...Like al-majhul tells stories, I will tell one...
A few months ago, when I was deciding where I wanted to apply, a mentor of mine in optometry, who's advice I take very seriously, told me "I wouldn't waste a stamp on SUNY." The reason for this: he said I had no chance of getting in. Well, I have an interview scheduled with them at the end of the month, so I'm more than half way to getting in.
Another short story: At the beginning of the semester, I called a professor at my school to ask her if she would let me into her molecular cell biology course even though I hadn't taken the two prerequisites for the class. She swiftly informed me that she had never seen a student pass her class who she let in w/o them. When I tried to respond, she hung up on me. I decided to show up to her class anyway, and afterwards, I approached her, and was able to convince her to let me in(only b/c I am a post-bac student, and poor grades won't really affect her). She was probably surprised then, when I got the only A on her first exam out of 40-50 students.
The point is, don't let negative advice discourage you. Let it make you more determined. The OAT is important to getting in, but there is always next year.