Have you checked to see whether your school offers any study skills support groups, or free tutoring? If not, most schools have an office of disability services. Even if your problems aren't serious enough to be considered a "disability," they may be able to evaluate your academic strengths and weakness, and point you toward appropriate resources.
Also, I do think it is a good idea to talk to your professor, but I think professors are often uninformed about study resources available on campus. If your professor doesn't have concrete suggestions about where you can go for help, do follow up on your own.
Don't let this get you down! Plenty of smart people have one or more areas where they struggle academically.
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