I personally do not use the word " sick" I prefer unwell or unstable.

I see no reason to not file, "most " people get denied at inital filling so then you can appeal and this is the point I say hire an Lawyer that mainly focus on disabilty If your still denied then you will have a court hearing, it a small room and you are just there with your Lawyer the judge and a employment specialist.

Be cause there was enormous backlog of cases it took me 4 years to be awarded SSDI .. You do get back pay to your intial filling date. Each state is different on how long it can take.

You have nothing to lose by filing now altho I expect there is a longer wait time with COVID messing the whole up..

Good luck