<p>Couple of thoughts for you:
Think you are on track for the most part. (You seem to know how important getting those board scores up is).
Particularly for Brown (I really think more so than some of the other same tier schools, although they all like to see this): pick something over the next year that is an EC that really requires and can benefit from your whole-hearted and significant time investment, and follow it with a passion. This will help show leadership and commitment, and hopefully self motivation. (and may help you define what you like and are good at as a bonus). You sound more like an art type major than a pre-vet. (But at a school like Brown you can do both.)
Some things to think about: pre-vet is very much like premed, and schools like to see a strong math and science background. (math scores, calculus) Brown has very few “pre-vet” students. The reason for this is that most pre-vet students go to strong schools in states that have Vet Schools, re the admissions chances for those schools. Also at least in the past it has been harder to get into vet school than med school. You need to have a long/ detailed “pre-vet” experience re working in clinics , research etc. That said, one of my friends at Brown (one of the best students there) was “pre-vet” and went to arguably the best vet school in the US, so it is possible.</p>