An important first step is to be evaluated to determine whether or not you have a learning disability. For many people, these evaluations take place when they are children but that is not the case for everyone. There are likely many adults struggling with unidentified learning disabilities.
I am not familiar with the disability services in your country. I would encourage you to investigate how you can receive a learning disability evaluation. Check with your local health department, hospital or the government personnel. They may be able to point you in the right direction.
In the United States, individuals with disabilities have certain rights that their employers, by law, have to provide. If it were determined that you have a disability, this would likely help your employer to better understand the difficulties you are facing with your job. It might also mean that your employer would have to alter the job requirements to accommodate your unique needs. This may translate into a job that is tailored to your personal needs and abilities.
Consider discussing your concerns with your employer. It might help to clarify any misunderstandings related to your work performance.
You also mentioned that you feel nervous in front of others. This anxiety may be contributing to problems at work. You may find it beneficial to see a therapist. Therapists are trained to teach people how to deal with anxiety and many other problems. In addition, the therapist might also help you to improve your time management and organizational skills. Gaining these skills would very likely improve your work performance. It might also increase your confidence level.
Below are links to two websites that provide resources for adults with disabilities. Some of the information provided on these websites are geared toward American citizens but there is general information that is universally applicable. I hope this helps. Please take care.