Stress can certainly promote hair loss, though such loss is temporary. I suggest you get a sense for how much hair you're actually losing by counting the hairs that come out when you comb over 3 days--if the total is under 300, you aren't losing as much as you think you are. I assume you don't have any bald
spotsBirthmarks - pigmented
Liver spots
Measles, koplik spots - close-up
Mongolian blue spots or patches.
Just for peace of mind, I suggest you contact a dermatologist to get a definitive diagnosis. But this does not sound serious or irreversible. I also doubt that your medications have a direct relationship with this, though the judgment will depend on when you started them.
I'm sorry to hear about your sisters' passing.
All the best.
Dr. Rockoff