That's alright. Unfortunately it is difficult for Filipinos/as to get visas for other countries due to obvious reasons I am sure you already know.
Doctors appointments are not really a tie and probably bring more questions than answers, such as adequate travel insurance and possible medical expenses if needed.
As you work freelance, this is also against you as you don't have a regular paying job with a contract etc that will show you will return to PH.
Overall your chances of getting approved are not very high, but the only thing you have to lose is the application fee.
There is no documentation required, certainly none of my documents were looked at when I went for my B2 visa interview. All the information is on the application form and they will ask any further questions. In your specific scenario I would probably bring a bank statement just in case they ask for your available funds.
I'm not sure on the current wait times for an appointment so if I was you I would book it ASAP.