i went to my doctors cause they had to verify my disability. don't know about doing it online but hopefully there will be more helpful info from others. the key tho is your doctors' agreeing with you that this is indeed the best way to go. have you talked with them about this?
also there is a company-allsup-that will take care of your applying. i'm sure there are other companies too. they take the monies you would've received after applying until you are accepted. once you apply this money accrues until you are accepted. so that's how you pay them for their help. the good news is that's their motivation in helping you get accepted.
lawyers will also assist you for a fee.
SSD can be difficult to get but i got mine accepted in record time.
so if you use a company/lawyer to help you with all this substantiating to SSD that is the kicker. but after that you receive your monthly check.
hope this helps.
and no i don't think calling them today will help unless you have questions about the procedure.