You do need to boost your GPA. Since you're about to start your sophomore year, you still have time. I would recommend finding other people in your classes that really want to do well, and study with them often. Most of my friends are people that study often so that studying all the time seems more normal.
You still have time to bring up your GPA. You still have few credits and it will make it relatively easy to bring it up. Just remember, if you have a 2.4 now, you will need roughly a 3.6 next year to bring your cumulative up to a 3.0. A 3.0 is still low for optometry school though, so aim even higher. It's a lot of work, but if you have the drive you'll be fine.
You also should remember that a low GPA can be countered with lots of in field experience, but you still will need a higher GPA than 2.4. Lots of shadowing, volunteering, and work at optometry offices will be a huge boost to your resume. The OAT is another way to show that your GPA is not a measure of your ability. Study hard and score high on the OAT and you'll have a real shot.
Edit: As KHE said, you aren't the first. There are many success stories on this very forum, so look around on the forum and relax. You've got a long way to go and stressing about it now is just going to make you lose sleep.