It sounds like you need to work with this doctor's office to get the paperwork filed correctly. Once that's done, if the doctor has you off work from August, the workers' comp insurance company should go back and pay you from August. Once you've got that taken care of, you may want to consider a change of doctors!
I can see where this may get complicated so you may want to consult with a good workers comp attorney. Find one here at www.avvo.com or at www.caaa.org. CAAA is the association for attorneys here in CA who represent injured workers. Or you can call me for a referral. Good luck.
When filing a claim for disability it is always your responsability to make sure the claim is filed on time and that it is supported by the proper documentation. I would suggest filing a new claim along with an updated doctors note. here are the requirements for making a claim;
Workers who suffer a loss of wages when they are unable to work due to a nonwork-related illness or injury, pregnancy or childbirth, may be eligible for DI benefits.
•You must be unable to do your regular or customary work for at least eight consecutive days.
•You must be employed or actively looking for work at the time you become disabled.
•You must have lost wages because of your disability or, if unemployed, have been actively looking for work.
•You must have earned at least $300 from which State Disability Insurance (SDI) deductions were withheld during a previous period.
•You must be under the care and treatment of a licensed doctor or accredited religious practitioner during the first eight days of your disability. (The beginning date of a claim can be adjusted to meet this requirement.) You must remain under care and treatment to continue receiving benefits.
•You must complete and mail a claim form within 49 days of the date you became disabled or you may lose benefits.
•Your doctor must complete the medical certification of your disability. A licensed midwife, nurse-midwife, or nurse practitioner may complete the medical certification for disabilities related to normal pregnancy or childbirth. (If you are under the care of a religious practitioner, request a “Practitioner's Certificate,” DE 2502, from the SDI office. Certification by a religious practitioner is acceptable only if the practitioner has been accredited by Employment Development Department.)
Here is the link for filing on line.
Try getting the correct paperwork form your doctor's office and get the paperwork refilled.
DISCLAIMER: David J. McCormick is licensed to practice law in the State of Wisconsin and this answer is being provided for informational purposes only because the laws of your jurisdiction may differ. This answer based on general legal principles and is not intended for the purpose of providing specific legal advice or opinions. Under no circumstances does this answer constitute the establishment of an attorney-client relationship.