I think that it is possible for you to improve your score with the right self-study strategy. You didn't mention anything about the study materials that you used--did you practice primarily from OG, Manhattan GMAT, Princeton Review, or Kaplan?

Take some time to study the following resources to get a sense of how to structure your own GMAT test prep:

https://beatthegmat.blocked
https://www.beatthegmat.com/wiki/

If you have some money, private tutoring might be a good option--but only follow through with it if you think you can't significantly improve on your own. I've heard good things about MGMAT's private tutoring. If you become a Beat The GMAT member, you get a 10% discount on their services: https://www.beatthegmat.com/discounts.html

Good luck!

I agree with Eric that it is certainly possible to do well by studying on your own but you need to make sure that you're making progress. If you aren't, then you may need outside help so that you understand how to study.

Also, do think about what Eric suggested re: nerves or some other factor that might have affected you negatively on test day. If you don't try to identify and minimize any such factors, then you'll likely have the same issues the next time you take the test.

If you need to use a private tutor, you can keep costs down by scheduling a session once every 2-3 weeks and then spending lots of time in the first session learning HOW to study on your own. Then you can do a lot of work on your own before you come back and meet with the tutor again for more instruction.

Effective study goes well beyond "I got this wrong. What's the right answer and why is it the right answer?" You also need to understand why you fell into the trap of picking the wrong answer. You also need to think about what the most effective process would have been for answering the question correctly, and as a result, what you should do in future on a question of that type. Also think about how to recognize certain question set-ups or issues on different (but similar) questions in the future. Etc. I can easily spend 10-15 minutes studying a single question after I've tried it for the first time.

Stacey's comments about analyzing your weaknesses are absolutely spot on. When I was studying for the GMAT, I would typically a practice test on Saturday for 3 hours, then spend 6 hours the next day analyzing my mistakes and trying to figure out question patterns that consistently fooled me.

When you first start studying, it's not a big deal to practice untimed, but after about 1-2 weeks of studying a particular question type, you should start timing yourself (from then on) on that question type.