The short answer is that you should look for help in understanding what is making the homework hard or slow for you, and then you should seek help for that.
If your parents do not understand or provide help, the school can. If you are not happy with the school’s help, talk to your doctor the next time you are there. Many difficulties in school can stem from physical problems, and they might be able to help you in ways that the school counselor cannot. Doctors (in my experience) are not always the most sympathetic about school problems (since they obviously did well), but they can at least recommend someone who can help screen you for potential problems such as learning disabilities, dyslexia, or ADHD that would interfere with schoolwork.
Are there particular parts of the homework that are hard for you, areas where you think you might need help? Are there things that you didn’t learn that cause trouble for you (for example, because you transferred schools and never had instruction in a particular area)? Or are there specific tasks (such as reading) that you think are slower for you than for most people? Or do you just have difficulty getting started, or staying on task? There is help available for all of these situations and more.
Many learning disabilities and other physical sources of difficulty in school go undiagnosed because people blame themselves for their difficulties. Learning disabilities are most likely to be undiagnosed when the person is very intelligent in other ways, because they tend to compensate for their weaknesses and hide their difficulties. If you think that you are having more than ordinary difficulties, do not wait to seek help because it can make a world of difference (it did for me — I went from failing to an A student with the right treatment).