rebooking of flight due to illness

hey all, just wondering if anyone has found themselves in a similar situation. I am sick and unfit to travel as recommended by my doctor, and i’ve contacted SQ customer service. they said that there are no available seats for next tuesday, wednesday and thursday even though i can see that there are seats. they’ve also canceled my flight which was supposed to depart tomorrow (to avoid the no show fee) but there are no guarantees on the rebooked flight, how screwed am i?