first off, don't start stressing too much just yet

get involved in a quality research project and work hard for your PI

work on honoring as many second year classes as you can

rock the boards - qbank by kaplan etc

be a work horse during your clinical rotations and honor them

you should be fine, try to repeat the class you failed over the summer or take a month off third year if needed, is it necessary to repeat the entire year? if you do repeat first year, make sure you take advantage of the time to work on research

You are behind the eight ball or in the deep hole. However, it is not insourmountable.
Priorities:
Excellent grades in 2nd, 3rd yr.
Excellent effort in fourth yr esp. during sub I.
Great step 1 and maybe step 2 scores.
Research and completed(published) papers.
Frankly, nobody cares that you are at a top twenty medical school. They care more about what you do at whatever medical school you are at!